You aren’t describing adultery. You are describing a date rape, and you were the victim.
If you speak about this to someone, it would have ruined a career alright! If you had disclosed what had happened back when you had evidence of the truth, it probably would have ruined hers. She acted like a sexual predator. Those come in female, too.
You might be dealing with a sociopathic personality, however. I would steer very far clear of her. She doesn’t want this known, so the chances that she will try to harm you with an accusation now is not high. She may even be very aware that there are witnesses who would attest to your version of events and not hers. (She may have even bragged about what she did!)
I would still suggest that you give her as wide a berth as possible in the most undramatic way you can manage. She is bad news. If you were in a position to make a credible accusation against her, that would have possibly protected someone else, but that ship has sailed. I’m not blaming you for not saying anything, just recognizing that you are not in much of a position to level an accusation because you have destroyed what evidence you had and did not get witnesses at the time. It is not just that you are male and she is female. I get a feeling that she is an accomplished liar capable of rationalizing anything she cares to do. She has all but told you that she has utterly snuffed out her conscience. Stay off of her radar, whatever you do.
Do you bear some fault for this? You failed to guard your purity, yes. That doesn’t mean you weren’t victimized with regards to the act itself. Talk to your confessor about it. You may want to arrange to have him there when you disclose this to your wife. (I don’t think you would survive trying to keep this a secret from her forever, even if it were something you know for a fact she would rather not know. Better to do the most gentle job of telling her that you can, and have support lined up to get through whatever follows.)
Keep in mind, though, that teaching victims to punish and blame themselves is what sexual predators do. You cannot take your willingness to take all the blame for this as a measure of your guilt. It is not.
Don’t be afraid of your wife doing a “me, too.” That isn’t very likely, particularly not if you come clean. If you think she’d want to cheat on you, work on your marriage.