I strongly believe this is one of reasons he is so interested on her. Deep inside his subconcious, he feels horny knowing the girl is fucking and taking loads of cum from different guys everyday and meeting him after.
I was in a "liberal" party group and met many swingers. One particular couple still makes me wondering human sexual fantasies/fetishes.
The husband let the spouse met guys on a 1:1 or 1:2-3 and he asked her to video call him to let him watch. Also, the guys should creampie her and she should go back home without taking a shower so he can do oral on her when she arrives.