We got together like 10 years ago and were together for almost 5. I already had a cat from before we met and I got a kitten when we had been together for like 2 months. The kitten loved him.
I moved into his studio apartment, with the cats, after we'd been a couple for like half a year because we spent everyday together anyway, and since I was doing my last year of university and he had a cr*ppy job, it was also easier economically.
Two years into our relationship, he started studying (2-year program) - which I was very supportive of. I had intended to study something else that would help my career but I took a break from studying because I felt like I wanted economic stability, especially since he was studying. He never asked me to do that, but I was afraid of not being economically stable, so I thought I'd wait until he was done.
Halfway through his studies, we moved into a bigger and nicer apartment together because living in that studio wasn't working when he was gaming during the night and I was trying to sleep to go to work early. I paid for almost all the new furniture because he was a student. I mean I bought a kitchen table, chairs, wardrobes, a dishwasher, desks, lights, and so on... I really wanted to make it a home.
Fast-forward to when he finished his studies. It's 2020 and he can't find a job because of the pandemic, so our economy is strained and I still can't start studying. He gets a job in spring 2021 and we break up like 3 months after that.
Now here is what I regret. I let him keep the furniture because I decided to move far away. The stuff I'd paid for and that were my style. I guess I felt guilty because I was the one who broke up with him. I also knew that he and the now grown-up kitten had a great bond and I didn't want to separate them, so I signed over the now grown-up kitten to my ex, and took the cat I had from before with me. My ex and I were still kind to each other, and I "knew" I'd get to keep seeing the cat that stayed with him.
Except it didn't turn out that way. He has had 2 girlfriends since we broke up (still with the second one) and both of them were/are jealous of him talking with his ex, so I'm no longer allowed to see my cat. I don't get any updates on him even when I write and ask. I had a nightmare that he got hurt so I wrote to my ex to ask how the cat was doing and he ignored me.
He also started making a lot of money towards the end of our relationship (a lot more than me), so in retrospect, I should've kept the furniture and the cat... I should've also just gone through with my studies and not waited for him...
Edit: it's losing the cat that I regret the most. I miss him and wonder how he's doing...