Man is implied to have had sex with partner's wife once and she spends the entire movie stalking him trying to talk him into getting involved with her. They eat a meal at a restaurant and she spends the whole time with her foot in his crotch, trying to tease him.
Men are shown going to a club of sorts which turns out to be a place to meet up with prostitutes. No nudity or sex.
Married man carries on a sexual relationship with a young female artist/painter who is implied to perhaps be a prostitute also. They are seen undressing each other. He is seen to remove her panties from underneath her shirt. They then have sex on a bed. He actually is kneeling on a bed holding her up in his arms while they have sex. Thrusting is seen.
Married man is seen to approach his wife amorously in bed while she actively rejects his advances. No nudity.