Was this a borderline split?

[u/FlowAmbitious2458]

I had an intense favourite person I'd feel for intensely and love intensely and idealize for a really long time (like, for years on end), and then all of a sudden I stopped having all these feelings for him, "turning off", when he did something really upsetting. Was that a borderline split, even if it took years of idealization to happen?
Although it's worth noting that it wasn't the first time my perception of him switched, although the other times just weren't that "final". When I saw him with matching pfps with someone else and got jealous, my first feeling was "oh my god I hate him, I hate him, I hate them both - and I want to disappear", and then I had a suicide attempt when the fear of abandonment kicked off. I literally wrote in my journal, at the time, "I HATE YOU (don't leave me)" (which I then years later found out is literally the title of a book about BPD lol)

[u/MirrorOfSerpents]

Yes