Yanno, the longer you pick apart every little thing this guy says, without taking action, the more crazy-making this is going to be.
I suspect the guy is just being friendly and doesn't even realize he's being flirty, or he is doing it as a part of his work. A lot of sales/personal training type of work behavior is very, very close to flirting. And it is meant to be. It's how they get people to come back and it is how they get people to buy more goods and services. If he can sell you whatever products they sell at the gym (yoga mats, whatever) or get you to renew, he gets a commission.
The guy has a girlfriend. The more I think about this, the more I suspect this is a sales gimmick. Then you'll really freak him out if you come out and ask him what is going on.