I've dated my boyfriend for 5 months now, everything seems to escalate rather quickly from the time we met until us being in a relationship.
He has told me before that he still kept in touch with his ex but they don't speak often only sometimes.
Recently, we were going through pictures on his digital camera and I saw the picture of his ex taken (Nov last year - his ex is married now) I didn't reacted until he told me that he still have her pictures on his mobile phone. He said he should have deleted BUT it's just him being lazy. He swore there's no feelings. That's when the skeleton is out ..
Two weeks ago, his phone rang at 12am and I asked him who is it - he said its just a friend he hadn't spoke to in a long time and it doesn't matter. In which, I found out (the same day pictures were found on his camera) that it was his ex contacting him. She said "I saw your girlfriends posting on Facebook and I just want to catch up with you" And her last line was "I'm not happy in my marriage", he told her I'm not cool with her contacting him like that. And told her to have a great week. BUT, later he email and said that she shouldn't text him on the phone and I would be upset. So he suggested to either email or skype.
I was really upset ..
After which I found out that he still told his ex he loved her last November but he congratulates her anyways for her engagement. She said she still loves him too but it is impossible for her to be with him because he doesn't believe in her religion.
That was the last their message exchange in Facebook was November last year ...
My boyfriend and I met in February this year ..I feel like my trust with him has been broken for him to go behind my back and kept in touch with her. I've never stopped him to NOT keep in touch with her previously because some people still keep it friendly but now, I told him it's either me or her. He said I'm the one and he wants to be with me. However, I can't seems to trust him anymore , the thought of him going behind my back and contact her creeps me out. He said moving on forward, he will tell me everything and not lie to me about it... Though I still can't digest or trust him.. I still love him...

What should I do? I'm broken and I'm on the verge of going down depression path again .... Please help.