Starting to have a feeling..

Well my guy and I have been together over 3 years and for most of that time we have had issues. The first time it was him being too close and over sharing with his ex about our relationship and discussing problems he was having with me. So that was a big issue we had. Along with him talking to this chick he had met on Yahoo pool years ago and when it came to her having relationship issues he would talk to her up till I got off work at 11at night so that became an issue. He was defensive about them talking but I was uncomfortable with them talking and texting as much as they were so I said it needed to end....well fast forward 7 months and we start to fight more and he pulls away from me more and more so I ask if he needs to tell me somthing because if I find out it will be much worse.. well he says no but I found out that they were talking but ob Skype, snapchat, and phone calls.....I looked through his phone and saw it all when I asked about snapchat I got lies and then it all came out he was emotionally involved with her....so I almost ended it. But gave him 1 last chance. But now I'm getting the feeling that something my be going on again or getting close to crossing a line....he is friends with this guy on the xbox and his now ex. But the ex has been messaging him and he is hiding it. I have told him to stay out of it and not ask but he seems to be asking and getting involved...so now I'm wondering what the real motives are....

Am I crazy or should I worry?