My advice to you dear: Sever the ties before its too late. My ex fiancee was a person alot like yours. Two weeks before the wedding I was shown his facebook messages revealing that he had been sleeping with several girls. They don't stop love. They will never stop.
That was it. Honest. As you can see on his profile I told him that he had his messages set to private/friends only. So he sent a request add this morning for a friend acceptance and I added him. He hasnt looked at my scorning message of "tell me what you want and gtfo"
Your partner it seems was trying to court me. He kissed the back of my hand, cheek, and "gave" me a dozen roses. Flirted with me and the like. Now he has messaged me asking me to come quietly with him. While I did accept his 2nd friend add, its only to deal with him and tell him to back off. I've seen this before, I'm been in this before, and I'm not about to be the "other women" again