Hi Dad. I am so sorry that all of this is happening. It is time for you to make the decision, and to act on it. The daughter, and boyfriend will have to leave. If your wife doesn't like it, well she can also leave. You have to hold your ground, and do what is right for you, and the other children involved. I would not allow any of this to take place in my home any longer. You are not being a prude.... or whatever word was used. You are doing the right thing, and being a responsible individual. Personally, I would hand the daughter her last paycheck, and let her know that she is on her own.
Once again, I am sorry that you are in this mess. I do hope that you stick around with us. Let us know how you are doing.