I found a letter from her ex!

Michael Says:
Me and my girlfriend got into our first fight since being together a year a couple days ago. So yesterday she posts something about jury duty on instagram and I had this feeling right away that she might have talked to her ex (he's a lawyer) Sure enough he comments on it and she comments back saying something like "now work your magic and get me out of it haha" She never talks to him and I told her in the beginning I was uncomfortable with it, but here's my real dilemma.

A couple months ago I found a letter in her drawer from her ex basically telling her he wanted her back. Saying things like "you were right for not wanting to see me a few months ago, I still want you" and "if he ever gets on your nerves give me a call". It bothered me to no end that she kept this letter but I ultimately just decided not to bring it up. Our relationship has always been so good in the year we've been together. We've never fought, we're always talking about the future and plus she's just not the type of girl I would ever think to cheat on someone. The fact that she was choosing me over him (who she dated for 6 years) made me feel a lot more appreciated in a way. So I let it go. But now it's starting to really bother me because this is where he said in the letter to contact him. "If he ever gets on your nerves let me know" And so that's exactly what she did or could be doing right now. It makes me feel like she's subscribing to this letter he wrote her and could potentially still have feelings for him.

I don't know if I should even bring it up cause she'll probably more than likely get mad. Except I feel like I have so much more to be upset about right now... 

Whatever happens next, someone's going to get upset anyway. There is no way you will be able to sit on this without it affecting your behaviour. There's an old proverb - sunlight is the best disinfectant. It's time to have it out with her. If she wants to go back to him, she's going to do it anyway, and the sooner you know the better. Honesty and trust are absolutely crucial to the survival of your relationship - if you want it to go the distance it's time to stop keeping things from each other right now.

It's also time for an ultimatum - him or you. You need to respect her choice, but don't be prepared to share! This is a big and painful test for your relationship I know but you didn't bring it about - they did! no more deception and secrets from either of you! Good luck