The problem is men are setting perfection as the standard. They are saying "I want a young, hot girl to be 100% faithful to me, forever". And if they don't get it, they say they failed. And if others don't get it, they say they failed.
I settled for a young, hot girl who wasn't 100% faithful, for 3/4 of a year. I do that every year just about. Yesterday a guy my age was telling me about his girlfriend, and the issues they had, and the breakup, and no contact - and I said "Wow, sounds like you dated my last girl, how old is she?" and he said 49.
We need to appreciate the small victories in dating:
1) You got her to notice you
2) You got her to feel attraction for you
3) You got her to initiate a
text conversation with you
4) You got a date with her
5) You passed the audition during dinner
6) You kissed her
7) You had sex with her
8) She came
9) You came
10) You made love to her
11) You thought you lost her but got her back
12) You got her to say "I love you"
13) The sex got better and better until it was mind blowing (for both of you)
14) You walked away with your pride when it broke down.
15) You waited until she reached out.
16) You saw her again and was unaffected by her, so she feels that power.
All of these were goals that you had to attain, and each should be celebrated. Her cheating doesn't undo the fact that you passed all of these tests (and hundreds more in her mind).
From that point you want to maintain it for as long as possible, but those are the only victories and it's all downhill from there.