I'm unhappy in my 4+ year relationship (I think)

First off I took a night job so I could work and get 40 hours of pay to support myself and my girlfriend (she works too). I am currently getting my Masters for free since I work 30 hours a week for the college (to get the tuition wavier).

A little information on my relationship. I have been dating my girlfriend for 4 and a half years just about. Im 22 shes 23. We started dating our sophomore year of college and we grew a lot together and made many memories and what not. I thought she was the one for sure. Never had it crossed my mind that we would ever break up. She has epilepsy and can't drive, or do somethings on her own (like swim) just for safety reasons. I have always bent over backwards for this girl and would be there for her through anything. I'd drop work and drive an hour away to the hospital she would be sent to after a seizure etc. I gave up many dreams for this girl (like living in the country since she would have to live near public transportation) but it was all worth it since I seriously loved this girl. She seemed so loyal and classy (which seems like it is very hard to find now-a-days).

This past fall, out of no where, she broke up with me. It was very cold. She seemed so emotionless about the whole thing. I pleaded with her, tried to get answers, tried to find out what I did, but all she would give me was that "I deserved better" and that "She wanted to try new flavors" and that "She was unhappy". It also turns out that one night at her work (shes a server at a hotel) one of the guests hit on her quite a bit and she fell for it. She ended up chatting with the guest for a while and then later called him and had an hour long convo with him. The only reason this hurt so much was because she said she got butterflies when he said some nice compliments to her (basically pick up lines to get her to go back to his room, which thankfully she didn't go that far). So at this point I am pretty devastated. I had invested so many memories, so much effort, love, and affection into her and our relationship and I had trusted her with everything. It might be worth noting that I grew up in foster care and have never really been able to fully trust people, not even past girlfriends, but I really trusted this girl.

Anyway we break up for about a month. I lost 20lbs, couldn't focus on school or work, and we still had an apartment together until December (when we were to graduate with our bachelors) so I was sleeping in the dorms again with some friends (felt really weird being a senior back in the dorms). I had never hurt this bad before. Everyone was right; I should move on, stop talking to her, stop hanging out with her, etc. but stupid love kept me after her. After that month though I think I was finally getting into a routine and was starting to feel a little more comfortable by myself, but then she started texting and talking to me more, and hanging out more, and physical stuff. Somehow we ended back up together. Part of me was happy but the other half felt so embarrassed. All my friends knew what she had done to me and knew that I deserved better but here I was back with this girl. Also worthy of noting that during the month break up she had 2 or 3 seizures and I always dropped everything and went down to the apartment to help her.

Well its been almost 8 months since we got back together and we recently moved into another place near the city a couple months ago. Things are going okay, but I always am open with her and honest and let her know that its hard to trust her. I tell her I feel dumb sometimes and that I am worried she will just do the same thing to me again after everything that I do for her, and that I never had a problem with her and guys before but now if a guy says a nice thing to her, is she going to get "butterflies." I feel so silly worrying about these things but at that same time I am sad and sometimes regret taking her back. Currently the crazy love that I had for her isn't there. I think she killed it. I am trying to give it time (since I have 2 more years left of my masters and can't shake anything up right now) and someday's I will have a day or week of feeling like shes the one, but then I'll go through a few days of feeling like shes not. I am sure people are going to say break up with her and that if I am not happy then move on (I am well aware of this answer), but I am looking for other advice/comments. Breaking up isn't really an option right now since we have a year lease together (I know, stupid but I needed to get a place and she was like the only option I had) and we have bills and such together. Am I stupid for taking her back so easy, or at all? Do you think she will do it again? I know I am not perfect , so I worked really hard on giving her even more attention and what not, but I am confident in saying that I am one of the better boyfriends out there for sure. I have to work 70 hours (for the once in a life-time opportunity to get my masters for free, and to be able to have enough income to support myself) and combined with the confusion and the sadness I feel sometimes about my relationship, it really is making things difficult mentally. Thanks for reading, any response is appreciated.