Can’t move forward

Me and my partner have been together for 14 yrs. Engaged for 6 yrs but never married. I found out 2 months ago that my partner had been on a regular basis meeting escorts or going to brothels for sex. He says he had been doing it for 18 months but I have evidence he’s been actively seeking them out for at least 6 yrs. Everytime I bring these affairs up he gets angry and won’t look at my evidence and says he doesn’t remember who he had sex with. Even though one of them he had contacted at least 13 times. He says he is sorry and that he was only doing it because I wasn’t puting out. 2 days after d day he told me to get over it and stop bringing it up but I need him to come clean before I can attempt to understand why he did it and start to forgive and try and make this relationship work because at the end of the day I do love him.