Recently I found an email on my SO Instagram, and he had called a girl gorgeous and was being very flirtatious (we had previously talked about having a 3-sum) ever since this has happened I have been very insecure and I worry about him cheating, I know we had talked about having a 3-sum. But , here the last few weeks since I found this , I have been having dreams of him cheating.. I'm worried and don't know what to do...