Robin Thicke watches as his wife 'dirty dances' with another man

Singer Robin Thicke and his wife actress Paula Patton have been together for 20 years..since she was eighteen and he was sixteen. Last night Robin performed at the VIP Room in Paris and after the gig, he watched with amusement as his wife gyrated with a partygoer....Twerking at one point.

Recently it was alleged by a groupie that these two have an open marriage. The groupie, 20 year old Lana Scolaro told Life & Style, that not only did she sleep with Robin, but his wife was just a few feet away. "I don’t think he cared what she thought. I was with him the whole night!” Lana said

Lana said that initially she pushed him away because he's married, but that Robin told her Paula was 'chill' and even encouraged Lana to talk to her.  See more photos after the cut...