Oh, gosh, yes! Don't feel dumb! You are only innocently asking a fellow exercise enthusiast to workout with you, it's not like asking him to cheat on any gf,
You're just networking, but with a bit of a plan. If he has a gf, or even a wife,
why shouldn't he excercise w/another? While you are out running, you can grill him, I mean ask him friendly innocent questions... like, what happened between him and your cousin's friend? (Make no comments, just listen.) And is he seeing anyone now? (Just smalltalk-like.) And what other things does he do?- because he seems like he's in such superb shape these days
If he's not seeing someone, tell him that if he ever wants company doing whatever he does (I've been told kick-boxing, preparing for a race, paddling competitively, fishing, surfing, chicken-fight gambling, drag-racing, riding his new harley, travelling to Brazil, writing the great american novel, learning to play some instrument, etc. as activities which have recently occupied him) you'd
love to check it out with him...
Whatever you do with this guy, tease him, then when he seems off center and needs to be reassured, give him a win with a smile or a wink... It's all a grand game, been played for centuries! And rather than wait for him to move, as Montana suggested, nudge him to move. 9 times out of 10, he will move when nudged. If he doesn't move, he's a dud. Move on! Just have fun doing it... I'm 44 and still enjoy the sensation of flirtation, of being a creature men desire to please... I'm just playing with your suitors fathers.
But it's all good, all fun! Get your skills down when you are young and you will be glad you practiced when you are old, trust me.