Love of my life cheated on me….need advice.

As the title says…the girl whom I presumed to be the love of my life cheated on me almost 5 months ago. We had been each other’s first and only. We moved in together too quickly (less than a year into relationship and we were only 18/19 yrs old). For a while we had been having some hard times and would argue a lot and stuff but I never wanted to let her go and I never stopped loving her. She used to tell me that she could never imagine being with someone else and would hate the idea of me being with someone else. Long story short…within the last year of our relationship she made it clear she wasn’t happy and was finally considering if being with me was best. I was slapped with the reality that she might actually leave me….we took a weeks break (still together but she went on vacation with family to “sort out her feelings”…. and in that time I was destroyed by the reality that she might actually break up with me and I changed completely….my outlook on the relationship, realized where I had gone wrong, and I just wanted nothing more than to be happy with her forever. When we finally got back to our place together after our separate vacations.. I was a new man and treated her great.Upon her return to our place, she was welcomed with a romantic setup, poems, and a beautiful “promise ring”. She accepted it and I was more than ecstatic because I knew that we would live happily ever after from that point on because I was so ready to make it the relationship we always wanted. The 7 days that followed were some of the best of my life.. The 7th day (after my “enlightenment”) we went somewhere very special to her for her birthday and had a great time and had great sex that night and everything was perfect…so i thought. The following day we went home. That night (the day after her birthday) she went to a friend’s house and ended up going over to this guy’s place who lives next to her friend and had sex with him that night and she was completely sober. I had been texting her because it was late at night and she still wasn’t home and typically she was never one to be out late. I was only texting to see if she was ok and when she would be home…she would text me back like nothing was going on even though she was hanging out with another guy whom she was about to have sex with. Anyways we will fast forward to the next morning and she was acting weird for a while until i finally pushed it out of her that she cheated on me. She was crying like crazy and I was in shock. Neither of us had ever been intimate with anyone else so this was a really big blow. Apparently she had hung out with this guy a few times before and NEVER told me about it (affair?). She says that she just thought he was a guy friend and didn’t tell me because she didn’t want me to worry. And also that that one night is the only time they had ever kissed and/or had sex. It seems obvious that she was seeing this guy behind my back for months because she was unhappy in our relationship..and she called for that week’s break to “sort her feelings” which really meant that she was HEAVILY considering leaving me to go be with the guy whom she was having an emotional affair with for months. So I think she chose him over the break..but came back to me being a different person which was probably overwhelming…
All that being said, I have been in unfathomable pain/anger/depression/everythingbad for the last ~5 months. All the while she has been trying to win me back and blah blah blah. She seemingly took responsibility for cheating, she has been going to counseling, and has mostly seemed genuinely remorseful and has said that she would never again cheat on me or on anyone else (assuming I don’t take her back) ever again because of how bad it has made her feel about herself, etc. Since we lived together when it happened and still had a few months on the lease…it made everything that much more difficult. But I will say that she went to live with a friend for at least a week and we had that time apart…as well as when I went on vacation for another week. I did actually instinctively make some positive changes (started working out again and getting tan…especially since i might be back “on the market” ..but not really anything beyond that). We ended up going back to cohabitating until the lease would end months later as we had no choice really. The cohabitating was unhealthy because I would have such severely negative emotions that would manifest themselves in the form of me crying to her, asking her questions about how and why she did what she did and wanting to know every detail about it all and would push and push and blah blah blah. A lot happened that I can’t even get into on her because of lack of time. But anyway since then though, we have spent time together here and there and have kept in contact pretty much every day via text. When I am able to suppress the thought of her cheating out of my head, I am still able to enjoy my time with her and love her….but sometimes that makes it that much harder when I remember what she did to me and I go back into a place of extreme depression/sadness/anger/etc. Perhaps the most painful part is that I NEVER thought she was that kind of girl which is one of the things that I loved most about her. It might also be noteworthy to say that this is the only time she has ever done this type of thing (allegedly at least..but I believe her).

*side note #1: I don’t think I mentioned: our relationship lasted about 3.5 years…cohabitated for about 3 yrs (or 3.5 yrs including after we broke up).
*side note #2: I did go on 1 date (with another girl) in the 5 month period since breaking up…it made me happy to have someone else paying attention to me and taking my mind off the pain…but it only lasted one date. It acted as more of a pill for my pain..the rebound relationship. And of course after it ended I went right back to being miserable without my ex.

If you have read this far, thank you. And I am just wanting some outside opinions on the following matters:

-Do you think someone like her can genuinely change (aka never cheat again)?
-Do you think trust can be rebuilt in this type of situation?
-Technically, if she didn’t love me at all she could have just cheated and said “fuck you” and left me…but she wants me back…doesn’t that count for something?
-It’s been almost 5 months since she cheated and and we’ve been broken up and she has still not gone looking for another guy besides me.
-Would it be humiliating for me to take her back? Would i look like a desperate piece of shit?
I probably already know the only two types of answers I will get though lol: 1. Yes, it is humiliating or 2. Don’t worry about what other people think, etc. etc.

****Perhaps the most important question: Do you think I should give this relationship another chance?

Any other advice on the matter is welcomed.

Your time and consideration is greatly appreciated.