How to drop a friend peacefully?

Okay I want to kinda drop a friend cus they've been making things worse for me but I feel guilty cus they had given me a gift me before. I've been telling them non-stop to like stop what they're doing cus it's just hurting me and both of us. Like I understand why and that stuff but I'm kinda just tired of giving them chances... For 12th time. Frankly Idk why I gave them this many chances but I don't like a friend who also makes my gf feel awful by constantly mentioning my dead ex around them. I don't want to lash out or fight, I'm thinking of ghosting but then that feels too cruel. I want to do it peacefully because there's already enough sorries and I'm kinda tired of dealing with their mental health.