An employee, and that’s what he is, will feel very uncomfortable going past whats appropriate in an employer/employee relationship, and you will lose a good personal trainer. Quite possibly you wouldn’t want to be friends with him either as once someone is a friend they may be more open and less polite than they would be to someone who is paying for their expertise.
Most people won’t object to the ordinary tip at Christmas, which is what you should do anyway, cash in a card is always appreciated.
But don’t think he will feel that it represents anything more than that.
I understand that if you are shy, someone in your life feels like a friend but that’s really not the relationship you have.
Do make the effort to see the friends you have and to meet their friends, to go to all the occasions where others will be present and get out there. Hard as it is, your need is showing, and someone in your employ isn’t the answer.
If you are just having everyone on…your need is still showing.

…….Um, people would definitely think you want to hook up with your personal trainer as like you are attracted to him, the way you say it; you want to get to know him better, then ask if it was a good idea to get him something like a card or gift certificate, and your not gay. Hmmm?
Let me think, would it be that you are actually looking for a good friend, role model, or brother like type or be like him on how he trained and kept fit through work outs.
People will be people in assuming what they know best…It’s you, that knows what do YOU want out of this? Think about it!

Dude I think you are psycho and Gay. I don’t know anyone that asks questions as strange as you.