How to end things with your partner?

I want to end things with my partner bcs of some reasons like her past. I got to know that she cheated on her ex(who was love of her life), had multiple hookups etc etc. She potraited me a picture of her that she really wasn't and I wanted to be in a relationship with that person. Now that I know things about her, i really don't feel like being with her as it is mentally draining me to the end. I'm also thinking of seeing a psychologist.

So at one point of time I'll be all ready to break things with her but after few hours that feeling slowly goes away. I feel the reason is I don't wanna be alone as I don't talk to people that much( i have friends). Second reason can be - She loves me v much and is ready to be a better person and all, I can see her trying to be that. So i feel what if I don't find anyone who loves me like she do. What I feel like will be better is if she leaves me. I can't hurt people feelings. Please people help me 🙏