What do you do if you kiss one of your friends?

Me and one of my good friends went to a bar last night to blow off some steam. Niether one of us had been out for a long time. She is married with a 2 year old and I have been dating the same guy for 4 years. We had some young guys buying us drinks(way to many) and dancing with us. We were both dancing with guys who turned us towards each other and started chanting “kiss kiss kiss kiss”. So we did. On the dance floor, back at the table, and several times in the cab(along with a bit of touching, to the delite of the cab driver). I ended up crashing on her living room floor with my head in a waste basket. I was awaken this morning by her 2 year old son playing with her husband. I felt so guilty, I couldn’t look her husband in the eye when he asked if we had a good time. My friend drove me back to the bar to get my car and on the way their where several akward silences. I got out of her car and said I’ll talk to you latter but I had a sad felling like it was the last time I would see her.
When I got back home I felt so bad when I saw my boyfreind. I felt like I had betrayed him. I have never done anything like this before. I don’t know what to do. Should I call my friend to appoligize? Should I tell my boy friend?