I have an ex boyfriend that calls and talks to me about his current?

girlfriend and their life,most of his complaints are about their life,money,and the fact that she has her 22-23 year old daughter and her 3 grandchildren living with her,I have told him time over time that I will still be his friend,but I will never ever disrespect my fiance,by cheating on him with my ex-boyfriend.But whenever he is around he always brings up what few good things we had going on,and is always trying to touch me!My question is should I give up the friendship to respect the man I love and respect?Or should I bring the two of them together to show him how much I treasure my new life?what would you do?Please only serious,honest and caring answeres.