Dr. William “Bill” Masters and Virginia “Gini” Johnson belong together. Showtime’s “Masters Of Sex” fans have known this for a long time but it’s only now that Virginia has realized it.

Last week, Bill (Michael Sheen) found out that Virginia (Lizzy Caplan) never married Dan Logan (Josh Charles). He met Dan’s ex-wife at an Alcoholics Anonymous meeting and learned the truth. Meanwhile, the sex researchers learned Art (Jeremy Strong) and Nancy (Betty Gilpin) are actually married. However, they have an open marriage.

Season 4, episode 4 of “Masters Of Sex” saw all the characters of the show – Lester, Betty (Annaleigh Ashford), Bill, Libby (Caitlin Fitzgerald), Bill’s lawyer Bram Keller (David Walton) and Virginia – attend a party thrown by Nancy and Art. But, the party isn’t a regular soiree. In fact, it’s a coats or keys party, meaning, that the gentlemen will pick a lady’s coat and they will have to spend the night with the woman who owns it.

The sex party in “Coats Or Keys” started with Art purposely picking Virginia’s coat. At first it seems like he really wants to sleep with her but the truth comes out late at night. He actually picked her coat because he knew she wouldn’t sleep with him. Bosses don’t sleep with employees. Ever. Little does he know Bill slept with Gini when he was her boss for several years.

Virginia learns that Art doesn’t want an open marriage with Nancy. His wife does. She didn’t want to marry him because she knew that she wouldn’t be faithful to him. Art questions Gini on her marriage arrangement also but she doesn’t spill the beans.

Instead, she realizes while discussing with Art about bosses sleeping with their employees, that Bill really knew the real her and loved her anyway. About time!

“Masters Of Sex” Season 4, episode 4 also saw Bill storming at the party to know where his children are since it was his night with them. Libby, high on marijuana, was accompanied home by her soon-to-be ex-husband.

At home, Libby demanded Bill go down on her and please her. He did. She told him that it was great and that they could have had 20 years of great sex life. Instead, Dr. Masters decided to find someone else to have passionate sex with. The husband and wife duo have seen the same night. Are they getting back together?

Meanwhile, Betty finds a homosexual at the party and spends the night with him at the office. She sleeps there because her girlfriend Helen’s family is in town and with her. In the morning, this homosexual and pianist answers a call making her think that she’s found a new receptionist for the office.

Elsewhere in “Masters Of Sex” Season 4, episode 4, Lester, who is upset with his wife sleeping with another man, has sex with an African American woman in his car.

The highlight of the episode was Virginia arriving at Libby’s house to give her her coat and finding a semi-naked Bill there. She confesses to him that she was never married to Dan and gets shocked when he tells her he knew.

“Masters Of Sex” Season 4 airs Sundays at 10 p.m. EDT on Showtime.

Masters Of Sex “Masters Of Sex” Season 4, episode 4 saw two people fans least expected to have sex hookup. Photo: Showtime