I've had a couple's massage with the wife before. It was at Bodyrotic about 9 or so years ago now.

Definitely a crazy experience, seeing the missus and ML go at it and then getting in the middle of it all!

The ML joined in everything, just don't expect sex or a BJ from her. Aside from that, you and your partner can do whatever you want.

Do your research, from memory Bodyrotic has a reviews page, so I read up on that before choosing