Son 19 was here when she picked up stuff today and asked her if I knew she was here .....if not she wasn't allowed in.
"But it's my house too" she responded. She didn't take too kindly to being told no it isn't.
G legally it is her house and unless you are being advised by a lawyer you and your son should not prevent her from entering the house.
There is nothing you can do right now to end the affair or get your wife back.
How does that feel? Crappy right? Used to fixing things? Used to finding a way? Familiar with the feeling that if you work hard enough, anything is possible? None of that applies now, there is nothing you can do. You need to surrender to that, grieve it and find peace with it. Fighting against it sets you up as their adversary, pushes them together and you away. If you continue to actively try to disrupt the affair and get your wife back, you will only dig your hole deeper and deeper, and that will be a debt that will take you a long time to recover from.