@BubbleTeaJunkie so sorry you are going through this.
I’ve been in exactly this position and I forgave. And forgave. And forgave.
It was a waste of time because the first time I forgave him he saw it as a green light to continue despite the sorrys and ‘I don’t know why I’m doing it’ and the ‘therapists’ - one of whom he ended up cheating with!
By the end of our relationship he wasn’t even being careful and would threaten that HE would end things if he thought I was ‘nagging’ him.
Things came to a head once and for all when after a night out he turned his phone off having said he was on the bus home and didn’t reappear til 5am. He’d met someone on the bus and gone home with her. He told me straight away, to wound me for asking him where the hell he’d been.
I had him out of the house by that evening but I’d wasted 2 years by that stage, waiting for him to respect me.
Any man who can lie and prospect and cheat - doesn’t matter if it wasn’t physical, it was cheating - like that and try to cover it with the performance you’ve seen is not a man who will change.
At best he will behave for a while and then go back to his old tricks and you challenging him will be ‘controlling’ and the reason he ‘has’ to look elsewhere.
Or he will resent you from the moment you take him back for revealing his disgusting behaviour to everyone.
You sound line a strong, capable and empathetic woman with a huge amount to offer.
Don’t waste any more of that on him. It doesn’t sound like he brings very much to the table.
His mother wants you to do what’s best for her, not you. If she really thought of you as a daughter she’d be threatening to kick his arse for you.
I know you’ve spent half your life with him but you’ve still got far more life ahead of you.
You can and will do better and that starts with knowing you deserve more than him.
Good luck 