How to cope with seeing ex and family

bones123

hey, just looking for some advice or perspective on this. I was with my ex for 6 years, living with him etc. We split for a couple of months, he was with another girl, we got back together, four months later he finds out she's pregnant. We do our best to work through it but I found it very hard, he was constantly getting calls from her, which to an extent I understood, he went shopping with her for everything needed for the new baby etc, wouldn't contact me during this time or anything. We split, kept in contact tho and kept meeting up, the child was born, he'd visit me with the child, he said he hoped we could make it work and had a visitation plan worked out, it didn't work out that way though in reality he was at the houseaall the time. I ended up going away with work for 6 months, during that time we were in touch 24/7, he sent flowers, cards etc. I came back, we met up, went away for a few weekends, all going great, did things with the child. and then I see him with the mother by chance, he said he was helping her buy shoes for the child. I couldn't deal with that so we split. He has since moved in with them, though has been on a dating website since and also has texted me to meet up saying he still loves me. But now I see him with her and their child everywhere. We're from a small town so it's difficult to avoid. However when I see them it's literally like a physical pain in my chest. I get totally devastated everytime. So my question is, how do I cope with this? sorry for the rambling post.