You need to get a therapist hun, it's not healthy to want to hurt someone especially when they're your partner. Either leave them or get some help and confide in them about your thoughts. Honesty is the best policy, even if they're upset they have the right to be. No partner should want to emotionally scar their s/o. But if I were you i'd get therapy and if that doesn't help you should break up. That's abusive thoughts.
sounds like intrusive thoughts [unwelcome thought, image, or idea that causes distress] to me, which the person can't control [not by themselves]. intrusive thoughts about harming someone is a common category of these thoughts
there are many ways to cope with intrusive thoughts, which you can google search [one resource i found: https://adaa.org/learn-from-us/from-the-experts/blog-posts/consumer/unwanted-intrusive-thoughts]
and remember, thinking about it does not equal wanting to do it
I guess only you truly know why. I don't know why you guys broke up and got back together, but it can create some rift in the realtonship.
I know with my previous ex in HS i got back together with him like 100 times because I was lonely.. And he was lonely I'm sure, but we both trusted each other a bit less for each time, and no matter how we apolgized it never truly healed the relationship.
I have a partner that I’ve known for about 4 years now and about a year ago we started dating for the third time and for some reason this time feels different I’ve been wanting to emotionally hurt my partner but I have no idea why whenever I talk to them I just have this urge to hurt them really badly and because of that i’ve been feeling guilty and Scared that one day I might say something that I would regret I actually love my partner and I don’t want to end are relationship just because of this error I have no idea if I should get professional help or if I should just I don’t know