Brother, you have been hit by two lorries, a heart attack and discovering infidelity. I am surprised you were even able to find this site and start going toward recovery just two weeks later. You have my sympathy but let me try to supply some practical advice.
First, you probably cannot make her leave without legal action and you are too weak at this point to leave. So make the best of it. Let her wait on you. She’ll probably try to show you how much she cares. Let her. But disengage from her emotionally. Go to the Healing Library and learn about grey rocking.
Second, just get over the embarrassment long enough to tell friends and family what she has done. I appreciate how you feel. It is humiliating to be discarded like this. But friend, you have no choice. You need support, physical and emotional. Tell your kids, if you have any.
Third, it is too early to decide whether to divorce or reconcile. As one member here advises, get on the fence and stay there until the right choice becomes clear.
Fourth, the only way for you to get out of this quagmire is to make her choose. Either she keeps the boyfriend or she keeps the marriage. There are no compromise positions that you can live with. The choice is hers. You cannot make her leave this guy but you can and must tell her what you will accept.
Fifth, is this POS married? If so, tell his wife. It is the moral thing to do plus in most cases it causes loverboys to jettison the affair. It also can help you earn an ally who may be able to flesh out the facts of the affair.
Sixth, you are normal, not stupid.
Sorry you are here. Your physical health is the first priority. If your wayward wife decides to leave you, you will need help. So, tell your kids, your friends, your siblings, anyone who will help you. In the meantime, get whatever help you can from her. She’s hired help who you don’t have to pay.