I slept with my cousin and i'm married.

First of all I am a married woman and my relationship with my husband is not great and has not been for a very long time. We only have sex maybe once every six months and for our four year anniversary we didn't even have sex or the night that we went out without children! So anyways, I never see one side of my family very often and on a particular weekend I went down to see them and hang out with them and what not. I went over to a family member's house and it was just a small group of people only me and two others, and we decided to drink. Drinks were going down smoothly, hanging out and talking was great, and then when one family member went inside to make more drinks for me and my male cousin, my male cousin well he kissed me. Not just a peck on the head or anything, but a kiss. The strange part is it didn't bother me. So eventually everyone went to sleep and him and I were playing video games and one thing lead to another and well you get the picture. I can't eat, I can't sleep, my mind is racing and I know that neither one of us wants our relationship to be weird as far as being around each other and other family members, but worries me is that it will happen again and I won't have a problem with it. I know that I am married and that what I did was wrong, but I don't know what else to think or how else to feel. I am confused and lost and I don't want to feel like this. I don't know what to do or how to act when I am around him. Do we call it a drunken night and leave it at that?