I'm in love with a married man...

So, I always had a crush on my brother's best friend. He use to live across the street and I would see him all the time. A few years ago, he moved away. He remained friends with my brother but, as for me, I've had no contact. I had recently ran into him 6 months ago and we have been in touch ever since. I feel like I'm catching really strong feelings for him. The problem is: he is married and has a kid. He keeps telling me that he is unhappy with his marriage and wants to get a divorce. His marriage has been dead for a while and his kid is the thread keeping it together. Yesterday, he caught me off guard by showing up to my apartment after yet another fight with his wife. He said he really could picture us together. According to him, I'm the one that got away. He kissed me and I found it hard to pull away. I feel really guilty but, it was honestly the best sex I have ever had in my life. I've never had such amazing sexual chemistry with anyone else. I really don't want to destroy a family but, what if he is the one for me and is really in a relationship that is unsalvageable?