Forgive yourself. We all make poor decisions at some point in our life. No one is perfct that was a confusing relationship with unclear boundaries. I'm not condoning your "revenge" but please don't fret over it.

People repeatedly abuse and mistreat people they "love" over and over. Every day, years. These are people that ... seriously mistreat others in life-changing ways. This isn't you.

I do think it's an unhealthy relationship and you might consider parting ways in a cordial manner.

Free yourself of guilt and take care. See a therapist and talk about it if you keep worrying about it.