OK, he may or may not be a player, but he doesn't have a magic wand.
I was in a similar position a few years ago, only I was single, DXP was married. We got back in touch through Facebook and remembered all the many ways we'd clicked, years before. He was going through a difficult time with a job he hated, getting used to the new area he'd moved to when he married his wife a few months before. I had problems with work and family illness, among others. It would have been so, so easy to fall into bed together.
But, we didn't. We talked, honestly and openly. We acknowledged that we still had feelings for each other, but that we were seeing everything through rose-tinted nostalgia. He said he'd been attracted to his wife because she reminded him of me; he recognised that a) he loved her, and b) the grass wouldn't be any greener with me, because we're similar! We came up with a list of reasons that we shouldn't do anything hasty, and we didn't.
But, we kept in touch. 3 years on, we exchange occasional emails, every month or two. He's more in love with his wife than ever. I went on to meet and get engaged to DP, who is similar to DXP but better!
I'm very glad that he was, and is, a part of my life, and I'm pleased that we were able to support each other through that difficult time. The intensity faded; the novelty wore off. The friendship remains.
So, my view would be that being in touch with him isn't necessarily a bad thing, but you already know that sleeping with him while he's still married would be. Give it time, patience and lots of talking, and see what happens. I firmly believe that people come into your life for a reason.
I wish you luck and happiness, with or without him.