It was a fairly short relationship (7 months) after I had just split up with ex-DP of 4 years. I found out about him texting multiple women and at least three of his exes, but I naively took him back after much begging from him and promises that he'd change. I just felt as though I couldn't continue a relationship with someone that I had zero trust in and therefore told him that we were done when I'd had a few drinks one night. In the morning I text him back asking for another chance to which he replied that he wasn't in the right place at the moment so I left it at that hoping he'd change his mind and contact me. I've since found out that he'd been having a physical relationship with one particular ex throughout the relationship however she claims that she knew nothing of him being with me. I confronted him about this but he denied it all and was adamant that she was lying despite me having proof. I suppose what I'm asking is whether I'd gain anything out of contacting him to ask for an explanation,(which he will no doubt not have), or an apology as at the moment I feel as though I cannot move on because I'm starting to believe it was my fault. Or will this just make me look desperate?