My ex still haves feeling for me, and my feelings are mutual, but he is married! I dont know what to do?

You see the reason my ex and I stop seeing one another because his parents found out I had a 1 year old, and kind of pushed him away from me! Now he is married and He still calls and texts and e-mails me and yes we slept together, but It was awkward bc he is married and i felt bad for his wife because i never want it to be that other girl on the other side of the fence. Should I just stop talking to him completely and just move on? Or should i just go with my feelings. Even though he ismy ex he is best friend too. What advice to you have for me and please dont be ugly! Just need someone to give me some good advice! I dont want to be judged! PLEASE