Ex Girlfriend

My husband has spent our entire relationship snap chatting his ex girlfriend, the only other one he genuinely loved and even wanted to spend his life with. I've talked with him about it over ten times, sometimes crying because I'm so upset about it and he doesn't seem to care. He always tells me he understands and that he won't if I don't want him to, but then continues getting pictures from her all the time. The last time we talked he told me he would delete her from the app and block her. Because of how things have gone in the past I really didn't trust that he would do it, and logged into his account. Aside from me, she was the most recent, having sent him a picture when he was on the road.

Everything else in our relationship is amazing, and no I would not leave him, so I really don't want to hear that from people. I want advise from what you have done or would do if you are in the same situation. I have talked with him about it so many times, so I must not be getting it across right. I don't understand why he refuses to keep her out of our life when he knows how much it hurts me.