"Halloween Delight" joke

A couple was invited to a swanky masked Halloween Party. She got a terrible
headache and told her husband to go to the party alone. He, being a devoted
husband, protested, but she argued and said she was going to take some
aspirin and go to bed, and there was no need for his good time to be
spoiled by not going. So he took his costume and away he went.
The wife, after sleeping soundly for about an hour, awakened without pain;
and, as it was still early, decided to go to the party. Inasmuch as her
husband did not know what her costume was, she thought she would have some
fun by watching her husband to see how he acted when she was not with him.
She joined the party and soon spotted her husband cavorting around on the
dance floor, dancing with every nice chick he could and copping a little
feel here and a little kiss there. His wife went up to him and being a
rather seductive babe herself, he left his partner high and dry and devoted
his time to the new stuff that had just arrived.
She let him go as far as he wished, naturally, since he was her husband.
Finally he whispered a little proposition in her ear and she agreed, so off
they went to one of the cars and had a little bang. Just before unmasking
at midnight, she slipped away and went home and put the costume away and
got into bed, wondering what kind of explanation he would make for his
behaviour.
She was sitting up reading when he came in and asked what kind of a time he
had had. He said, "Oh the same old thing. You know I never have a good time
when you're not there." Then she asked, "Did you dance much?"
He replied, "I'll tell you, I never even danced one dance. When I got
there, I met Pete, Bill Brown and some other guys, so we went into the den
and played poker all evening. But I'll tell you... the guy I loaned my
costume to, sure had a real good time!"