Ex boyfriend troubles!!😭

Jillian
Guys, I really need help. After an on and off again relationship for two years, my ex and I finally broke things off. It was supposed to be a mutual break up except for the fact that that night, I find out he's actually with the girl that I hated and started shit in our relationship. I couldn't handle them being together and even though we said we were gonna be friends, I didn't want to see that all over my social medias so I blocked him on everything and cut him off.
3 months go by and he texts me saying how much he misses talking to me and misses just being comfortable with someone. I no longer hate him and feel the same. He was my bestfriend, how am I gonna just cut him off completely? But it's bringing back feelings that I thought was over and now I don't know what to do! He's still with that girl but when I asked him if there was a chance we can get back together, he said "of course there is" I value his friendship but I don't know if the things he's done in the past is worth forgiving..