She started making excuses for not doing things with me.

I scheduled time for us to take a vacation to northern Wisconsin together right after her birthday and a week before she tells me her friends (who just happened to be an all male soccer team she played with for years who all had never met, but hated me) decided they wanted to do something with her that weekend because "it was the only time they could all take off". I called her out on it and told her that was bullshit and we had planned it for months and I felt humiliated that she would just drop plans with me at a moments notice for a last minute thing from her friends.

Then about 6 months later we were supposed to go to a wedding for a close college friend of mine and two weeks before she tells me she doesn't want to go because "[I] would have more fun without [her]" I told her that wasn't the point but that I wanted us to enjoy all these things together but I caved and went alone.

Well before this I had already set up the present I wanted to give her for her next birthday because I knew it would be hard to do last minute. Soccer is a big part of her life and her favorite team is Real Madrid so I bought tickets to their game in NY against AC Milan and purchased plane tickets from Chicago as well, probably totaled around 1.4k for everything. She then started making excuses for not doing the bare minimum once a week date night we had set up because of our schedules. I couldn't deal with it and went to her house to explain why it was upsetting me and how we could fix it. The look on her face the moment she opened the door I couldn't even think so instead of working it out or even explaining my reasoning I simply told her we were through and went to my buddy's to drink it away.

I actually prefer that she didn't get an explanation to help her realize her faults and that she messed up a great thing, because fuck that she'll just repeat it forever and never be happy.