Married man with kids...what do I do?

I met a married man, at first I had no attraction to him and the relationship was all business.(He is a cop and I was a victim of a crime).He would come see me almost everyday at my job and our friendship grew.But there was still no hint of us liking one another.Also,he is 38 & I am 23.So one day we were having a long conversation & he told me he needed to tell me something.He said that he likes me very much but unfortunately nothing can ever happen since he is married and has 3 kids.He was never inappropriate with me so I couldn't get mad.But our friendship keeps growing &it's obvious that we both have extremely strong feelings for one another but both of us want to do the right thing. I see that no matter how much we try to keep our distance,it doesn't work. The relationship is strictly platonic (with moderate flirting) but its clear that the feelings are incredibly strong.He's said that he's in a very unhappy marriage but doesn't want to ever lose his kids. Any good advice?