Loving on a man with a girlfriend

Alright this is probably gonna be a long one, because I'm going to make it as descriptive as possible... I will make a note that I believe in energy and circumstances and that everything happens for a reason, though I still long for advice.

Let me start this out by saying that I don't like guys easily.. OK, I like guys easily but I always get over them very quickly. My "crushes" never last. I'm a nineteen year old female, going on her second year of community college. I've met some really great people and great friends in my college career, but something entirely new to me has happened...

The very first day of one of my classes, I had entered the class early, and began staring at my desk, looking through the syllabus, because I am a good student. All of a sudden I feel this magnetic wave of energy and I look up to see this guy walking right by my desk. We made brief eye contact while I thought to myself, "that wave of energy came from him?" Based on his appearances (at the time) I would have never suspected such an immediate connection. He sat a few desks behind me and soon after I left it at the back of my mind and I didn't make much of the situation.

So this class has a break and resumes in another room (lab). I sat at a table that was full except for one other seat, the one right next to me. It was soon occupied by a girl (who later became my friend), though she randomly decided to relocate to a different table across the room that same day. The boy mentioned before (let's call him Tom) then took the seat after the class started, thus becoming one of my 4 lab partners. I'll admit that I was excited and already contemplating the circumstances, but once again I brushed it off. The day went by normally, with friendly conversation, but with a bit of a focus on each other, and he stained my mind slightly (I thought of him a bit outside of class).

The next lab day came around a week later, and then I discovered he smoked cigarettes, and we smoked together after class (yes I know this is a horrible habit and I am in the process of quitting). We hit it off pretty well and laughed a lot together. I felt strangely comfortable around him, and it seemed that he felt it too. We discovered quite a few similar interests, and parted after a cigarette.

The next class day (not lab), he walked in late (which he does frequently) and we made eye contact and thus he made his permanent seat the one behind me. We once again smoked a cigarette after class, and we hit it off even further. I started to adore him, and really enjoy his company and our chemistry. We had driven down to the gas station by the school together, for him to purchase a pack of cigarettes. There were a few arm brushes here and there, but I contained myself. I then discovered he had a girlfriend. I also discovered that he was several years older than me, but this didn't bother me as much as him having a girlfriend did. He also made a slight comparison of me and his girlfriend. I tried to put him in the back of my mind, but the whole "you always want what you can't have" thing started kicking in and I really started to dig this dude. (Though I never made a move on him and still have not.)

Over the next few weeks we started a routine of smoking a cigarette after class, me walking him to his car, and him driving me to the place at the opposite end of the school, where I usually hang out between classes. He would drop me off there and drive away, but always leaving with my name. "Bye, [name]". And I'd give a simple "see ya!".

He came over a few weeks later to get something I offered him, and to study for a test we had coming up. We briefly discussed his girlfriend, but I still do not know how long they have been together or how serious they are together. The day I had invited him over and we exchanged phone numbers, he had mentioned in a slightly irritated voice how he had a lot to do that weekend, which included his girlfriend visiting him, but he still came over that weekend. We had some intense unintentional staring contests and he called me as soon as he got home, "I made it home safely," and asked some questions about the thing I gave him (which he offered to pay for, but I said was unnecessary) (alright the "thing" is a symbiotic culture of bacteria and yeast used for brewing a health drink). He also thanked me a lot for it.

A week or so later he mentioned something about "only going to the movies when he has a girlfriend". (just a side note - he didn't say "my" girlfriend, just "a" girlfriend, though I may be looking too far into this). He also gave me a $40 worth gift, an aide to help you quit smoking.

Anyway, we just continued being friends and enjoying our great chemistry. Only flirting through eye contact. Nothing physical. Some abnormally long eye contact sessions, looking to each other when funny things happen in class, etc. We always hung out after class together though. And we always helped each other with our experiments. We always make eye contact when he comes in late to class, and give each other a smile, but we don't always talk immediately. We both have other friends in the class, however we have become good friends only with each other, and it is just the two of us when we hang out after class.

Lately, he's been encouraging hanging out together more. He mentions his girlfriend less (he hasn't mentioned her at all the last few times we have hung out, I guess I'm not even sure if they're still together). We have grown closer and my feelings have grown more, and I can't see how he wouldn't feel the same way. He does not at all seem like a "player" type, and seems to be a very loyal boyfriend. He seems like he's usually shy around people. He's also not the most attractive guy, or rather, I didn't find him attractive when I first saw him (now I think he's very attractive). I don't mean to sound cocky, but I would say I am an above average-looking female. The most flirting he has done with me, or me to him, is just joking around a lot with genuine smiles, and a sort of "look" in our eyes. We occasionally poke a bit of fun at each other. He also gives me pretty good body language, and I return the favor. We do not do any physically touching flirting (then again, I don't do that with anyone). (We've bumped feet accidentally while studying without apologizing, but it's not like we played footsie or anything).

I might also add that he's never been the first one to text me, and we usually don't text for very long. It's almost always ended by him not replying to a text from me. I never send him another text after he doesn't respond. He has called me a few times though, and I suspect he may be more of a call-rather-than-text type, for he usually responds to my first text several hours, if not a day, later, starting the text with "sorry it took me so long to reply".

I'm probably just over-thinking this whole situation, but I just can't get him out of my mind now. I went out on a date recently with someone else and had a great time, but it quickly fizzled away and Tom clouds my mind once again. I could probably move on if I really tried, but I really do not want to stop being his friend. I really enjoy his company!

I'm not really sure what to do. Should I tell him my feelings, or just continue being friends with him? Or something totally different? Help?

I'm a Scorpio and he's a Pisces if anyone cares about that besides me... xD

(Hahaha if he ever saw this he would totally know it was me posting it. How common is this situation? :P Whatever...)

I would walk away... If he were single, it'd be a different story. But he has someone.