My best friend (who is male) and I have a bit of a strange relationship. He is married yet we share a very...

intimate relationship. We are not physical in any way yet our conversations have on many occions led us down a path that would be considered an emotional affair by some. I know that we both carry feelings for each other that would be considered more than just friendly. Where things start to get complicated is that he set me up with a friend of his a few years ago who I have been seeing very infrequently for about 2 years. Neither of us were really looking for anything serious but I started to develop stronger feelings for him and said that we couldn't be physical unless we were dating. He emailed me this weekend to invite me to attend a banquet with him this coming weekend. I have been waiting for 2 years for an email along these lines. The trouble is now that this banquet is also for my best friend. He will be there and he gets so jealous when I am with another man - even though he shouldn't. I don't know whether to risk upsetting him by going or should I skip this banquet?