O.K. D...well, I saw this post after I got your PM so now I understand....
Anyway, I've been where this guys is now. If you can believe it, I wasn't always as "flirty" as I am now. When I got married I really hadn't experienced life...so-to-speak...so, when I got divorced I decided that I wanted to be with several different types of females just to see what was out there...I guess the old term of "sowing your wild oats" or whatever applied. That's most likely what this guy is doing. He was probably locked down in this prior relationship and either wasn't happy or didn't get treated right and now that he is technically single, like Johnae was saying, he probably just wants to explore his sexual tastes.
Now, my advice to you....don't be this guy's "friend with benefits"...you are better than that and you deserve better than what he is giving you. As far as pursuing a relationship with him....this guy is older than you and should be past the shit that he is pulling. I would say drop it and stay single for now until you find the guy that is right for you............................................... ...............................like me!