Advice on partner?

I feel really low in life and I’m struggling so I just thought I’d ask for advice.

Soo.. whilst I was pregnant, I found out my partner had been cheating on me at work and sleeping with his colleague. (I was 20 weeks pregnant, the girl also knew he was with me as I found the messages of her guessing the gender!). He was having sex with her in the car I sat in everyday, completely oblivious. I had to get tested for STIs in the end as I was worried he could’ve effected the baby’s health, which was so embarrassing as I’ve only ever slept with him.

Fast forward to now, our son is now 1 years old and we are back together, but I just cannot shake the heartbroken feeling. He still works at the same job (he hasn’t been promoted or anything and the managers treat him badly). He tells me that he wants to leave but he just hasn’t, regardless of my anxiety of the possibility of him cheating again. It has now been way over a year and he’s still not left.

Am I wrong in thinking that if he loved me and wanted me to move on from what happened that he needs a new start? I’ve even got him interviews for jobs he told me he wanted and he just ignores them. I feel like I’m wasting my time. Has anyone else gone through this?

Please be kind, I’m fragile🌸