Legal Question in Family Law in Maryland

Yes, adultery is grounds for absolute divorce in Maryland.

It can be, assuming you have done nothing to condone or forgive her behavior since you learned of the adultery (including having sexual relations with her). But the practical question is, assuming the adultery was ten years ago and there has been no subsequent inappropriate behavior, is your first option to end the marriage, rather than to consider counseling? Obviously, it's not a lawyer's role to tell you whether to stay married in view of your discovery. That's a decision for you to make. But before coming to any conclusions that have major ramifications, you ought to speak with competent domestic relations counsel and consider talking to a therapist on your own. Good luck.