Sorry to hear samson but what a mess.
As toffer said it would be a miracle if she didn't have an affair. It probably started before she became a dominatrix, most likely with the coworker she hang around with. Once she became a dominatrix the gates opened and very likely she had multiple affairs with multiple guys.
You should have left way back when she asked for an open marriage. Usually that term goes with serial cheaters, not the regular run of the mill cheater. You might want to check if she has secret accounts on hook-up sites and her phone bill if she has been getting calls from strange numbers.
Do you have an idea what they did with the college roommates? Or if she was even there?
She says the divorce is something I wanted not her.
True but she was the one that destroyed whatever was left of the marriage. Divorce is only a paperwork after this point as this is not a marriage. She is shifting the blame on to you, do not accept an ounce of the problems she created.
Also get tested for STDs right away.