Awhile ago, I had written about my experiences of working out with my ex-boyfriend. Couples who workout together are pretty glamorized. It's not always all sunshine and sweet-gym-nothings. Although my ex and I were both gym buffs, we were different sort of athletes. I was into weight training and powerlifting, and he was into running-- which was OK. But sometimes, we just wanted to do our own thing.
You can actually check out that card here: The Gym Couple: Lovers Or Fighters?
I think that I am at a place where I would workout with a significant other again, but I think I would prefer a partner who was more into weight training. That's totally NOT a must, just a plus. It goes along with having common interests.