It just takes SO much to make me hate a person. Is that unhealthy?

I mean just in general it’s extremely hard to get me to hate you. I think I have dealt with so much bullshit and abuse in my life that it’s made my skin pretty thick, so you’d have to do something very cruel or truly vile to hurt me or affect me negatively. I have a friend who is an ex coworker and she had started a lot of crap at work and tried to get me fired once. I do not care, that’s just petty to me. first of all with my job I knew that it was “the truth would prevail” kind of thing and it did, so I never got fired. What I did was confront her about it and talk it out and I befriended her and the bullshit stopped. My SO cannot stand her because of the things she pulled, I listened to him and tried to pull some kind of response out of myself that mirrored his response but it’s just not happening. I literally do not give a shit about what she’s done in the past. She’s not doing it anymore, We’ve made amends and she can be my friend if she wants to 🤷‍♀️ he thinks it’s unhealthy to allow people around you if they’ve done you wrong and feels that I let people walk on me. He feels like I don’t give myself justice so I wanted to ask: is this all unhealthy? Should I give a shit more?

Edit: oh shit I didn’t mean that we are like bffs, I may give no fucks but she’s certainly not my BFF. I am just friendly with her, and talk to her but don’t confide. I mean that I hold no resentment towards her, and we are friendly to each other, that’s about it. I should have clarified that more ☺️