My sisters boyfriend tried to kiss me and now i feel really guilty.?

i went clubbing with my sisters boyfriend - we are really good mates anyway. We got very drunk and when we got home (my sister wasnt in) we decided to just talk for a bit, so we just sat in bed and talked. he ended up hugging me coz i was upset set and when he let go he tried to kiss me. i leaned away and said no, he listened and i left the room to go to bed soon after. he hasnt mentioned it since and neither have i and i just cant even look my sister in the face. obviously my sister is my sister and i love her but her boyfriend is also one of my closest friends, so i have no idea what to do!? i had sort of calmed down about it, but now i keep thinking im seeing him giving me THAT look, more confused now than i started out. you could cut the tension between us with a knife, i dont want it to be like that, i want to do my best to keep my friend. x