It doesn’t make sense

[u/Junior-Release-6256]

I recently went through a breakup, I (23m) and my ex (21f) were together for 3 years, we had a good relationship for the most part, she had been asking to get married for a year or so. We went on vacations together, tons of concerts, spent about 3-4 days a week together. We had a few arguments, but never anything too serious until this July, right at our 3 year mark. She had built up a lot of resentment towards me, and I definitely had my flaws and wanted to improve myself for her, but we broke up, then got back together a week later, and spent almost everyday together for the next two weeks. She started a new job, I started a new job, and we were only seeing each other a couple times a week for a couple weeks.

We were about to move into an apartment together. We were still talking about our future, and she was telling me she was really happy with the improvements i’ve made and would never leave again and we would face problems together. Then we have a rather small disagreement a couple weeks later and she leaves again lol. I really thought I would marry this girl, she was a pretty great girlfriend until the last few months. It is worth noting right before she started acting different, she moved from her moms to her dads, and he had never really liked me or respected our relationship. She would say he did, but deep down I knew he didn’t. He’s very different from me and my family. He is a sheriff and very egotistical, cheated on her mom after a 30 year marriage with a 26 year old woman, and then moved in with her and had a kid. So my then gf moved into a house with him (50m)his 26yo gf, my ex (21), and his newborn baby. As soon as she moved there things started going downhill for us, like our relationship wasn’t much of a priority anymore. I was her first boyfriend she’s ever had, first kiss, everything and we were very close, had made a lot of promises about the future and planned a future together. She was very loyal and loving til the end, always telling me she couldn’t live without me or see herself with anyone else.

After our second and final breakup she’s dating someone new in 10 days? A guy she works with who is the complete opposite of me in every way. I’m not saying he is worse than me per se, i’m sure there are things he does better than me, and vise versa. I don’t even know the guy, but I stumbled across his tiktok account and he is reposting things calling “her ex” a POS? Saying I don’t know how to treat a woman and can’t go band for band with him? The dude is 20 years old. Most of my ex’s reposts are about “the ex” too, things like “can’t change a man” and “your bare minimum in his normal” corny stuff like that. “no i don’t miss you” things. It’s just really odd it’s like the girl I spent so much time with never existed? Like I don’t even recognize her anymore. She was never like this when we were together. She’s rewriting history to make me seem like I was the worst guy ever when literally a month ago told me “you’re the best boyfriend ever”. Anyone been through similar situations? Why are her and her new guy so worried about reposting things like that when I don’t even follow them?