I stepped into my own pile--what do I do now?

I've been married almost 10 years. My husband goes through these periods where he's not ual. I always blamed it on his age, as if he were going through male-menopause or he was bi-polar or something like that. He won't talk to me about it, so I don't know for sure. I figured since he wouldn't talk to me, maybe he would talk to someone he didn't know...I set up a fake mail account and contacted him, striking up a friendship with him. My online persona with him has made it blatantly obvious she wants a fling and he is making arrangements to "meet with her and see what happens". My heart sank when I read that line. I wasn't expecting him to potentially cheat on me, but that would explain his lack of interest in me, if he's getting it somewhere else. What do I do now? Do I continue this lie and arrange to meet him and see if he shows up or do I not reply and close the account and live with what I know? My guts are all twisted in knots. This man is the love of my life but this knowledge is eating me up.