Should I tell him I am having an affair?

Im 28yr married for 7yrs and have been a rocky relationship for the majority of 5yrs. He has cheated on three diff occassion-last being 2yrs ago. We broke up on one occassion about 31/2 yrs ago and I met someone else. I was become very close to this man when my husband and I tried to "make things work" I have since had a on again off again relationship with this man. My relationship with my husband has come to the point again where divorce may become an option. Iam falling in love with this man-I have only been intimate with him one time during the last seperation from my husband. Ive told my husband Iam no longer happy with and want it to end-his reply to that is he will do ANYTHING to make it work, but he has asked me if Iam seeing someone else. I have not told him in fear things may become violen. Because domestic violence has been in our history (last time was about 3yrs ago) There are children involved (his and ours) and a child that the "other man" has custody of. HELP!!!!