It all started with a letter.
You knew it was from his former flame, the one that had plagued him for a few years and had made it near impossible for Arthur to accept your love because he felt undeserving of it. You can't say your opinion of the woman is high but neither you or Arthur talked much about her, and for that, you were glad. But now she was back, in some way, shape or form, and you're not sure if you want to pry. Were you really foolish enough to think that after the years you and Arthur spent together, he'd really just go back to Mary because of a letter? You can't tell, since his face remains blank as he reads it and he only lets out a little sigh after he's done.
Arthur tells you himself what the letter says, even letting you read it to prove he's not hiding anything from you. It wasn't in his nature to do something like that to you, though he can tell the subject is agitating. You try to keep your face neutral as you read it, it's pretty standard as a letter but it's clear she's calling on Arthur for help with something; help she probably didn't deserve, considering she was calling on him most likely for the 'outlaw' side of him that she so quickly rejected.
You wish she'd just stayed in the past.
"You'll be goin', then?"
"...I might." Arthur is gauging your reaction, probably waiting for some type of fight to break out over it, but you keep your cool. You can feel the jealousy boiling up in the pit of your stomach but it wasn't your right to control your lover or his actions, and you weren't going to start acting like that now. You hand him back the letter and give your best smile, though you know he can tell it's fake. He could read you so well at this point you don't know why you bothered lying to him.
"I'd go just to hear out what she wants." He nods his head slowly, not buying that you're completely okay with the situation but knowing you're too stubborn to admit it; shaking his head while a smile tugs at the corners of his lips, he can't help but feel his chest swell with all the love he has for you. You were a stubborn woman but there was no doubt you were looking out for him. "She starts askin' you to run away with her you better be runnin' in the opposite direction."
"'Course, darlin'." He leans down to press a kiss to your forehead, relieving some of your worries, but unfortunately, not all of them.
Before he leaves to go talk to her, something he decided for himself he needed to do for more closure of his old relationship, he bids you farewell. He'd be a fool to run out on someone like you for someone like Mary- Mary wasn't a bad person by any means, but she had proven where her loyalties lie, and Arthur had plenty of time to realize what he wanted from a partner in life. Someone who could accept him for all he was, criminal or not, and who wouldn't be ashamed of who he is; maybe that sounded stupid, considering the fact he was part of a gang who stole and killed, but that's why he didn't entirely blame Mary for leaving him.
It led him to someone who made him feel things he hadn't known were possible.
"I'll be back." You watch him ride off, and from that point on, you're a bundle of anxiety.
Stupid thoughts, your overactive imagination, continue to plague you as the day goes on about all the things Arthur and Mary could be doing. It doesn't matter how often your brain informs you that Arthur would never do that to you, all you can see are visions of he and Mary... doing the things that couples do. You're distracted from your chores around camp, being scolded by Grimshaw (and nearly slapped) more than once, to the point you decide you might as well hide out and hope she didn't find you again, seeing as you were getting in trouble either way.
When you hear your name being called you flinch, expecting another scolding from Miss Grimshaw but being surprised to see it was another person who wanted your attention.
You should have known the supreme father figure that is Hosea would notice your pacing restlessness around camp, trying to keep yourself as busy as possible as you rid yourself of negative thoughts surrounding Arthur and Mary (and failing miserably at pushing away the thoughts and keeping yourself busy). But you can't help but have this nagging feeling that Arthur was the one that got away to Mary, just like she had been to Arthur until he found you. A replacement? You probably wouldn't go as far to say that, especially considering how different you most likely were from Mary (and how many years it had been before Arthur got into another serious relationship). Hosea, though not a relationship counselor by any means, didn't seem to have much of a problem listening to your worries.
"Has he ever given you a reason to think he'd run out on you?" He asks bluntly, and you look away, flustered. You're both surprised and not that he managed to immediately pinpoint where you fears lay, it was a very scary power of his that came with years of experience.
"...He hasn't."
"I've known Arthur a long time, and the man says what he means. Yes, Arthur loved Mary, enough to propose to her, but that was the past. Mary might not stay there, but I believe that love will, partly due to the love he has for you and partly because he's learned his lessons." Hosea leans back, keeping his eyes on you.
"You gonna pull a Dutch and tell me to have a little faith." The serious look on Hosea's face drops, replaced with a smile.
"Faith in this situation would be good, yes, but I'm tellin' you, you have nothing to worry about here."
When Arthur returns to camp later that night, you want to be the first to greet him, run up to him and say 'Thank God you're back!' but you think that'd give off the wrong message. You didn't want to make him feel like he didn't love you enough just because of your own insecurities, you didn't want to make him feel bad for re-visiting someone from the past, someone you had to remind yourself came before you were even around. Do you think younger Arthur would've fallen for you, or were his experiences with Mary what ultimately led him to you? Fate was a funny thing, doing what it wanted, never seeming to operate in a straight line, but always having people end up where they needed to be.
Made you worry the lot of you may end up at the end of the rope if fate truly was real, but you're sure now you're just rambling in your head to make yourself feel better.
You hide out in your tent, thinking about the worst case scenario, wondering what words he could say to break your heart and then you could cushion the blow for yourself. It was easier to think that way about yourself, to not be confident enough to think someone would pick you, because it felt like if you did, maybe the universe really would spit in your face and have him pick her over you. A stupid, foolish thought, made my an anxious brain and a heavy heart that feared the worst, you really were just making this situation... worse than it had to be.
You should've asked the other ladies on their opinion of it, but you didn't exactly want them to know about your inner thoughts, either.
You're distracted by the two different sides of your brain fighting, telling you to have faith, explaining to you there was no reason to worry and if you were that worried, you should be an adult an actually talk to your lover. Thankfully, the latter option is going to be easy, considering he just walked into your tent to talk to you about it. Your eyes linger on him, going to his lips, and then his feet, suddenly feeling ashamed.
After all the awful things you'd thought today here he was, standing in front of you, just like he said he would.
You feel like you don't deserve the hug he gives you nor the way he tilts your chin up and leans down to give you the softest, most reassuring kiss afterward. You grab his shirt, the material bunching up under your fingers, and keep him close to you, refusing to let him go. He doesn't mind the closeness, he never has, and his one hand rests on the curve of your lower back, rubbing it like he normally does when he knows you've had a stressful day.
"How'd it go?"
"We talked, I helped her with her brother. Told her about you." He whispers, his hands finding a comfortable place on your hips; he pulls you a little closer, looking at you with such warmth and affection you feel even more like an idiot for doubting him. "Said she was happy for me."
"Think she'll be callin' on you again?" Arthur chuckles at this, hands squeezing your hips.
"Don't think so."
You don't say 'Good' like you want to, instead pressing forward and wrapping your arms around his shoulders to bring him into a tight hug. He's more than happy to return the love, peppering kisses along the parts of your face and head he could reach; you can't help but laugh, as this was the exact opposite of everything you'd imagined would happen. There's some relief in thinking Mary is dealt with, back in the past where she hopefully stays even if Arthur was kind enough to help her out one last time, or you can at least hope. Even if she did ask for more help, even if she missed Arthur and wanted to be with him again, did that matter?
Because he chose you.
And he'd continue to choose you, over and over, even at the expense of his own life.