Exactly. She got game.

She wanted another/new man, so she conveniently 'breaks up' with her steady.
So she can 'get her groove on' - guilt free.
After she does her thing... decides to go back to her old man...
most likely because the new guy was just a 'one-hitter-quitter'.
Or he didn't want a whole relationship (with her).
So they both got what they wanted.
But hey OP... it's ok... because they 'were not together' at the time... get it?
Btw, I'd ALSO place bets on the fact that either...
- There was MORE than 1 guy. Maybe 2.
- Or maybe just 1 guy who smashed SEVERAL TIMES. And they did it ALL. Even stuff your boy hasn't tried yet


- Or maybe the 1 dude she admitted to 'being with'... is probably NOT THE SAME DUDE she actually slept with.
If so, the dude she 'admitted to' is the guy who is 'most forgivable'.
i.e. The guy who your boy will convince himself: "It's gonna take some time to get past this... but I'll still marry her anyway"
She wouldn't DARE mention the ONE name that would make your boy say:
"Awww .. HELL NO!! NOT HIM!!! PACK YO' SHIT!!"
Plus, I think the REAL guy is 'still in the picture', somehow.
Like a co-worker. Or Boss. Or 'just a friend' to her.
(Who might have even attended their wedding.

)
Or she still talks to him. Trust.
(The OP never mentioned if his potna discussed whether she still in contact with him.)
If he stays in the relationship... it's gonna take a loooong time for him not to feel a certain way about her.
Cuz if the shoe was on the other foot... she might not EVER get past it.
Women forgive. But they never forget.