You 當初 were not 非移民. You were F2. Sue you can sue that guy ofcause.
Anyway, comfort. I think your case will be approved 100%. Because you had legal status (F2) when you entered USA.
The rule is if you had legal status when you entered USA, you can get GC by marrage, no matter you lost status or not after then.
If you do not have legal status when entered USA, you will get big big trouble.
Good luck to you and your hu*****and