Or it might have been a TV show, but I vividly remember watching it on HBO or showtime some many years back. The movie basically was about(atleast what I remember) a wife cheating on her husband with a young neightbor kid. I remember this one scene where she was having a party at her house and the guy she is cheating with comes over and sits underneath her dress ( giving her oral sex) as she stands holding a big bowl above her head and then her daughter walks in on them. I swear to god the guy she was cheating on was Sean Astin but I cannot full remember. If anyone knows what I am talking about please share. Thanks.

It partially sounds like the Alarmist with Kate Capshaw, David Arquette, Stanley Tucci, and Ryan Reynolds.

Their is a scene where Kate Capshaw is on the kitchen table, changing a light bulb I think, with David Arquette under her skirt giving her oral pleasure. Her son walks in and catches them, Ryan Reynolds plays the son. It sounds a lot like what you are describing but not exactly.

If you are sure about Sean Astin then it could be Staying Together but I think he was the kid cheating with the married woman, he wasn't the husband.

Hamburger... The Motion Picture (1986)

I think. there's a scene which is similar to what you described

Hmmm, I might have to check out all three. I think I phrased what I said wrong though, I might to say the guy she was cheating WITH I think was Sean Astin. I do remember another scene now, that the wife was outside doing some gardening and he comes over and kneels down infront of her putting his hands between her knees, and she pulls her dress over his hands and he fingers her.

Lawn Dogs (1997) with a very young, very good (IMHO) Mischa Barton.

http://imdb.com/title/tt0119506/

I think we might have a winner