Breaking up because of his ex

In a way he is choosing her if he knows you won't tolerate it and he still does it. If there really is nothing there, then some people would say it shouldn't be a big deal. But they have a history and he's not being straight with you about the situation. If he's not honest about that, who's to say what else may be kept secret? You're not being stupid if you thought it was fixed. Now he's backing away from what he agreed to before. So the "you, and only you" part was not true. It would be different if he was divorced from her and they had children together.
I hate it when women devise tests for guys, so I never thought I would say this. But I wonder how he would react if you told him that you had turned down a lunch date with some guy because you had a boyfriend. But since he has her, now you think it should be OK to go. But it's really curiosity. That wouldn't likely solve anything. And in the long run would probably make things worse. He could get jealous or he might think it's great. But I don't think it would wake him up and get her out of the picture.

Tell him you feel that way like she is more important then you are once an ex always an ex if he is still talking to her after he broke up with her she still likes her and with her liking him when this all started you should have confronted her because this has to do with you and her and he is stuck in the middle.

Your a woman (womens intuition) you can feel somethings not right. He knows their relationship bothers you, (not saying he's deliberately doing it), but he allows it to continue, the ball was in your court along time ago. If their "Little friendship", has been going on a year, and your not feeling good about it, you have to put your foot down,( "Time Out). You have to decide when you are sick and tired, of being, sick and tired. It's all mental really, you have to control what you think about, be aware of what's on your mind, if it's something that stresses you out, (makes you feel sad) STOP! , and think about something different , something that makes you feel good (positive, and if that means replacing your thoughts of him, so be it. ("if it doesn't make you feel "Good, then it must NOT be good" And if it turns out thinking about him makes you feel sad, you have to go with your feelings. . You should suggest to him, that "you are willing to give him some space, so he can figure out what he wants to do, because you can't handle his "little friendship, and you needed some space too. If he's cool with that, then let it go, , if not, you have to "SHOW him you are not okay with that, he has to see, that you won't accept it, you don't have to get ugly with him, mean or loud, but, literally take your space, (for a little while anyway), go with your feelings.