I'm in love, but I shouldn't be

I'm in love with my best friend/co-worker. We started working a project together a couple years ago, we've become close because we travel together and we have to be very open due to the nature of our business. I didn't expect this. Nothing has happened and it won't, for now. He has been married for years to a wonderful woman but they have separated a couple times in the last few years, both of them citing growing apart and falling out of love. They have tried to not throw away years together which is admirable. This time they have legally separated and are living apart. I would never make a move while he's married. I respect myself and his wife too much for that. He wouldn't cheat, which is another reason to love him. I can't tell anyone, all of our friends are mutual and know him and his wife. I refuse to put someone in the position to keep secrets. After a work function with our friends we were the last ones standing after a night of dancing, we sat on a rooftop talking. A little liquid courage and he made a slight confession that he wasn't sure how he was going to find someone meaningful after divorce but he hoped there were more women like me willing to give used goods a shot. I almost burst into flames. It took everything in me not to make a move but it would have been tainted if I did. There is no emotional affair. We talk openly but until recently he very much still relied on his wife emotionally. We are best friends and our group is very close so this is not weird. But it seems we are both thinking the same thing. As much as I can't bring myself to root for divorce, it seems inevitable. And lusting after a married man has me weighed down with guilt even if I haven't even told a soul. I just needed to say it. I can hardly wait for the opportunity to love him. The hardest thing I've had to do is keep my hands to myself when he's within an arm's reach.