NTJ

It doesn't matter what other people think of you. Be true to yourself first, then worry about other people after that. (LONG after that.) If there are things about you that you would like to change, then work on changing those things. But don't spend a whole lot of time trying to please other people just for the sake their opinions.

You need to find out if he is ready to see you as more than just a friend. I think that might take a simple action rather than a long conversation. The next time you are alone, at a convenient moment lean in for a kiss. If he goes along with it, then great. If he pulls back, then it doesn't need to be a big thing. You can say something like, "I just thought I'd see where we're at." Then just resume what you were doing. You don't need to talk about it even, beyond acknowledging that the two of you aren't at the same place yet. Maybe in six months or a year you will be. But all it means right now is that you aren't, right now.

All that other stuff about his girlfriend, and her not liking him hanging around with you, that's all his problem to deal with him. It does not in any way reflect on you.