Confused about my ex's visit

My ex boyfriend and I were very much in love. We had a strong bond and friendship. We were very close but I had some personal issues I needed to take care of so I could let go of some past traumas. I asked him for some space and long story short he was devestated but agreed. Within a week he had a new girlfriend and within a month she moved in. He did not know her before we broke up. I know that for a fact due to a mutual friend. We had our argument about that and then I did not contact him and continued to try to work on myself. I wrote him a closure letter after some time and it was very positive. I took it to him at work and he didn't want to take it. That same night he came to my house and talked to me and took the letter and left. I was ready to close that chapter in my life even though I loved him still. 2 days later at 2 am he was knocking on my bedroom window and I let him in to talk. He talked of the good times and talked about the problems he was having w his new girlfriend. We talked as friends but then he kissed me and told me that letter I wrote effected him and told me how good I looked when I took it to him. He held me and kissed me several times. I am so confused. With the love that we shared I am sure he still has some feelings for me. He also talked about our good times. By the way we are not kids. I am 43 and he is 42. What do I think of this visit? I know what I want to believe but I need an opinion from men and women alike. Please let me know your thoughts if you read this. Thank you

Anyone who gets a new GF in a week has security issues or had new GF on the side. How is it that this mutual friend knows this for sure they did't know each other? You make it seem like not knowing this girl is a positive thing, who knows anyone in a week? What should you think about his visit:1) that your letter indicated to him that he still had a opening with you.2) 2 days later at 2 am he's knocking at your bedroom window? (Why not the front door?) this is known as the " 2:00am possible booty call"or 3)the 2:00am "confirming your intentions is what he thought they were." Anybody that moves this fast while in a relationship or getting into a new relationship should signal a red flag. Agree with SUSIEQQ -only when he end his relationship with his GF should you get involved with him.