Ex as a Friend?

I decided to let go this guy who I've been having feelings for 2 years (mutual feelings TBH) because he was meeting someone on January. I was determined to finally let him be happy since we can't be together for out-of-our-hands reasons, but knowing me too well, I decided to block him from everywhere so I don't write him, but forgot to do it from SC. I really thought that if he was serious about this girl he wouldn't look for me, and at the same time come one, I blocked him from everything. Two months later, on March, he decided to write me to SC because he wanted to know how I was, etc. He told me he was really jealous about the guy who I was that day but he understand that he's wrong being jealous and doesn't matter with whom he's with he'll always have feelings for me... fast forward we met again a few days laters and we couldn't help ourselves so things happened... after that I decided to stop everything for a thousand time, he told me this girl was serious thing, so why should I have to be in his life? Why we kissed, make out and say each other that we missed each other? He wanted to see me again before the end of April because he was getting married with this girl because her visa was going to expire and he didn't want to lose her (what a jerk, but at least was honest... still jerk). That day was the day I decided that I wasn't going to see him again, for what? To keep hurting myself? Thanks but I have (somewhere) a little of dignity. Since March I've been struggling with depression and haven't stop thinking about him like he did something to my brain that I just can't stop. I told him when I'm ready I'm going to see him, it was a lie because I wasn't ready to see him one last time. So time passed and he got married at the end of April. He wrote again 4 days ago, this time I went straight to my honesty, told him that I can't see him, he don't know what's going on in my life, I've been struggling with depression, I still have feelings for him, but I'm not going to do anything because everything I want is peace and this feelings go away. He keeps insisting in stay as friends, he wants to help me and be there for me, be my support, etc... I mean, all this pain and depression it's because I can't stop thinking about him and because I can't stop my feelings for him. We talked before everday, since then once a month maybe more if I don't write, but still think about him every single day... how the f* I can be his friend and let him be the one who help me, when I have strong feelings for him? He keeps saying that it will hurt more if I separate myself from him, he says he care, and more things that sometimes I don't even care.. 

I really need someone to help me with opinions and honesty, how can you move forward when someone who you love, ask you be your friend, when deep down you know that will hurt more.