Need help

I have a 2 year old pyrenees/ american bulldog mix he’s around 110 pounds. He was a rescue from an abusive home but i got him when he was roughy 3-4 months old. We did lots of socializing and play dates with dogs and he was great. Then once he hit around the 1 year mark everything started to go down hill he became dog aggressive and people aggressive. We worked with a trainer and that seemed to help. Then he got fixed and since then he’s been terrible. He has severe anxiety and can not be around other dogs. He is fine with people outside as long as they ignore him but if they come in the house he freaks out. My partner has recently moved in with us and he has known her almost his whole life and loves her. But since she moved in when they are home alone while i’m at work he pees on the furniture and the floor and growls at her. I’m just not sure what to do to help him. I love my dog and want to help him become better i’m just not sure how. Any advice will help thank you!