Re: advise needed
If/when you decide to end this marriage, send a certified letter to USCIS. Let them know that you are withdrawing your sponsorship, and that you suspect he married you ONLY for immigration benefits. State in the letter if you already filed for divorce or plan to do so asap.
BTW, there’s no point in doing this once he gets the 10 year permanent GC. If you plan on doing this…do so BEFORE the conditions are removed from the 2 year card.