Why does he act this way with me? Does he like me?

One of my closest guy friends has been acting differently around me and I think im starting to have feelings for him. He has a girlfriend, but the way he acts around me makes me wonder whether or not he has a girlfriend just to have one, or if loves her but has strong feelings for me also. I would never to anything to threaten there relationship, they’ve been going out for awhile and I respect that. Here are some examples:

1. We’ve had a class together since freshman year (were both seniors) and always sit by each other and do projects together.
2. He sits behind me this year, sometimes he’ll play with my hair or write his name on my shoulder. He jokes around with me a lot and teases me, we make each other laugh
3. He waits for me after class so we can walk out together, he tries to make it not noticiable but sometimes it pretty obvious.
4. Last year, our teacher asked our other friend if we were going out ( he had his girlfriend at that time too) and I think our teacher this year thinks were dating too, sometimes he’ll look at us talking and just smile and when he was absent, our teacher asked ME if I knew where he was. I said I don’t know ( I really did know I just said the easiest answer) then our friend jokingly said “why not, isnt he your boyfriend?”
5. We did a group project last year, and we had to make a music video. we did ours to “love story” by taylor swift. I was juliet and he was romeo. This year, I get a voicemail from him at 1AM singing “I am romeo and you are juliet” over and over and “its a love story baby just say yes”. he’s mormon, so it wasnt a drunk call. When I brought it up, he would joke around or change the subject. 6.We both play volleyball and he wants me to go to all his home games to watch him play. I missed 2 and both times, he said he was so upset with and kept looking for me in the stands. he says it in a joking way, but apart of me feels like he may be serious. 7.We talk all the time in class, and online too about anything at all.
6. He called me babe a few times the other day, hes never said anything or called me anything like that before

he’s always been a flirt, and I try not to encourage anything but it has never been to this extent. What does this mean?!? is there something deeper going on or is it not the big a deal?