Almost had sex with my best friend/room mate's boyfriend while she was out of town...

[doctor remulak]

I am Doctor Remulak.

[oOBatteryOo]

I think I'm going to stop drinking. I'm going to try going to an AA meeting tonight

[oOBatteryOo]

My friend works at a bar/bistro near me. We've been friends for a long time, along with his wife, my boyfriend, and coworkers One night around New Years, we were jumping his coworker's car and after she left I gave him a ride back to his car. We sat around talking, he kept telling me to break up with the guy I was currently dating and then he pulled me for a kiss. At first I pulled away, but he puled me back in, and we made out. After that I avoided him. He called me to ask for something I borrowed from his wife so I met him up after work. I told him I was super uncomfortable and that I didn't know what to think. He said there was nothing going on between us so I was relieved. When I was walking back to my car, he pulled me back and we started making out. Rounded first base against my car then went into my car and we went to third (ie: fingering and blowing) Mid blow, I snapped out of it, stopped, and kicked him out of my car. It's been a month since then, but he still texts me almost every night...tells me he misses me and can't get that night out of his head.
I'm so ashamed. It's bad. I don't want that to happen again, but I want to be friends still.
What should I do? Should I tell his wife?
TL;DR I'm a horrible person and have done everything, but sex with my married friend. I want it to stop, but he doesn't. What should I do?