I feel for you being cheated on that totally sucks
But agree with pps your subsequent posts show a lack of maturity and internalised misogyny and a lack of understanding on how the world and relationships work.
I'm almost 50 I've always dated, had relationships and had fwb situations with younger men that's always been my preference, some have been much younger esp the fwb, 15, 20 years younger at times. They were mature adults who knew exactly what they were getting into.
I'm also a larger woman which under westerns beauty standards may not now be considered conventionally attractive (though I was when younger)
Attractiveness is not ONLY based on looks, it's based on personality, chemistry, connection too. Plus some people prefer larger women my brothers best friend is very attracted to larger women he's tall slim and "gym fit" himself, his first wife was 24+ dress sizes while they were together his 2nd wife is at least a size 30 and they have an amazing relationship.
If you think conventional beauty standards are all that matters you will be repeatedly disappointed attractiveness is far more complex than that.
Kindness and confidence are HUGELY attractive.
Leave them be they know what they did nothing you say will make an iota of difference to their conscience or any guilt they may feel.
Move on, work on ACTUALLY building your self esteem rather than basing it mostly on looks (which fade - quickly!) and address your internalised misogyny too, perhaps through some therapy?