Dude, if you are going to spiral after a 2 month casual hookup relationship ends then you need to not have those in the future. This girl did nothing wrong. She told you she wasn’t interested in anything serious and then ended things when she thought (rightly so) that you were taking things too seriously. Next time don’t sleep together until you have established that you are both interested in something serious.

Any chance your wife may be down for an open marriage? If she’s not interested in having sex with you maybe you can stay married and just get laid on the side? Cause the other 2 options are you staying sexually frustrated forever or divorce.