Struggling to move on from a break up

My boyfriend and I were together for a year and half before we broke up. When we met we just clicked, both so smitten and it quickly got serious. A few months in we had a silly row about something and he totally shut me out, i had no idea what was happening but he told me to leave him alone, blocked me and then a week later came back in tears saying sorry and he didn't mean it. He told me that he had battled depression for 15 years and that as soon as there's something that upsets him his instant reaction is to push that person away and shut them out. He said at the time he doesn't think about how it would affect me and it's out of his control, he just gets swamped by a big black cloud and can't see me or speak to me and that i have to let him deal with it on his own. The whole relationship carried on like this and although when we were good we were great, it began to really affect me. I couldn't help but take it personally and blame him and try and guilt trip him into seeing how hurt i was. I hated it that these dark spells would lead to us missing things together like weekends, parties and even a holiday.

He did have couselling, and things seemed to improve after that, he seemed really positive about where we were heading and agreed that we needed to communicate better when he was feeling down. I then however found out that he'd met a girl on a dating website during our last week apart and that he'd been texting her inappropriate things. This was hard to take as the whole month he'd been saying that we were the best we'd ever been and he knew we could make it, he'd actually been flirting with someone behind my back. He said he just needed to chat to someone who didn't know his issues and that it helped him feel normal. I tried to accept it as we were due to go to a wedding and then a 3 week holiday 3 days later. We had a good time but the feeling of not being good enough and knowing that i'd been lied to consumed me and in the end i blew up, i said it was over and walked out on him however after a day to reflect i decided that i did love him and that maybe we should just sit down and talk and then start again as it had only been recently we'd been discussing a baby.

By then his depressive episode was in full force, he wouldn't reply to my text, emails he blocked me on all social media and if i turned up at his house he wouldn't come out. 3 weeks later he got in touch and said he missed me, we saw each other but it was hard, he just seemed so angry and kept talking about how me rejecting him has affected him and he felt like he couldn't make me happy. After than i never saw him again.

It's been 4 months and he refuses to see me but speaks to me alot. If i don't contact him then he will contact me and say he misses me, but then as soon as i say i miss him and want to make up he gets nasty again. I am totally devastated, i've had alot of time of work and am starting to lose myself because my mind is consumed by him. I've chased him to the point where i can't chase anymore. I call, text, email everyday. He blocks me, and then a while later he'll unblock me. Numerous times he's said he loves me and will come over...then just doesn't show up. Then he'll tell me he doesn't love me. He's told me that this is all my fault and that i'm bipolar and mental, when i try and point out ALL of the times that he's left me and then come back and the cheating and lies etc he doesn't register it and makes out that that's nothing compared to how i've treated him by walking out on him and then changing my mind. In the past 2 months he's called me various names, told me that no one will even love me, that i'm pathetic, ugly, he'd see me but only if he could use me for sex. Then once in a while he'll say he misses me and maybe wants to try again.

I know this man is the one with the problems not me, but i've let myself become totally dependant on the need for contact, even if it's abuse, that i cannot move on. I have no idea what to do and never realised that a relationship could be so emotionally abusive. i think the main thing that i'm struggling to deal with is that someone could say all of the wonderful things that he'd said in our time together, how he could have wanted a future with me etc and then at the click of a finger he hates me. For someone who admitted to me that his biggest issue was feeling rejected and not good enough - why would he do this to me? Making me feel rejected and not good enough?