Tell your wife that either (i) she has sex more frequently, (ii) her son moves out or (iii)
When you see it coming, duck!
I'm sorry to hear that. The good news is, it doesn't sound like an LL issue, just that she's embarassed to be overheard by her son, which makes sense, but at the same time, it's hers and your house! If he doesn't want to hear/see things that are a little awkward, he should leave. You two are doing him a favor by letting him stay. Maybe putting it this way to you wife would help.
Also, when dh and I have guests over but still want to have sex, we usually close the bedroom door and turn a loud action movie on or something lol. Also running the dishwasher/washing machine/dryer may help create enough noise that your wife would be more comfortable. You shouldn't have to give up your sex life completely if you have a guest. Her son MUST know the two of you have sex...
Does he watch tv at night? Maybe you can sneak a session in when he's distracted. Sneaking around can be kinda fun sometimes :)
Best of luck! Talk to your wife and try to see if you can come up with a realistic compromise.
If all else fails, buy her some jewelry. Always works for me. Haha!
The son and his girlfriend move out in 2 weeks.
the reason him being there is interfering with our sex life is that we live in a recreational vehicle.
The son is an adult, he knows people have sex.
Let's assume for a moment that staying with her father, and her son being in your place are valid reasons not to have sex.
What was her interest in sex BEFORE those events?