Hmmm…
Well, maybe let them have use of the master bedroom for sex and you and your wife talk about what SHE wants to do as far as ...... arrangements. She might want to be with you. I wouldn’t plan on things too much, let it unfold and allow them the freedom to enjoy each other.
Is this a Hotwife thing, or cuckold, or “My wife just fucks this guy every now and then?” If you and your wife are on the same page then let ‘em do whatever. Involve yourself with watching (maybe?)… have them record their fucking and ask your wife to blow you, fuck you, whatever while you listen to a session And she tells you about it.
The important thing is, if this is really your first time to be there in over 13 years, to be on the same page as your wife. Are you good with what she wants to do? Is she good with doing it and you being there? If you give them your marital bed, will you be ok with that a month from now? We don’t share our bed and that’s right for us. May not be for you.
Hope it all works out!