Effects of sexual behavior exposure to a 3 yr old by an older teen child and her boyfriend

Recently, my 3 yr old started trying to kiss me on the lips (even though we already had established that we give 1 kiss on the cheek at a time) and nibbling/licking ears of others in the family. I would explain that this behavior is inappropriate and tell him not to do it. However, it has come to my attention that my older teen daughter had been making out with her boyfriend in front of my other children (ages 13,14, and 3). We have always had strict rules about boys being in the house while we were out and were sure to have someone (us or the younger siblings) in the living room with them at all times to avoid this type of behavior, but the others never told us what was going on. I asked again last night who taught my 3 yr old to lick ears and my 13 yr old admitted his sister and boyfriend were doing this in front of them. Is this considered sexual abuse? My daughter is now 18 (since mid August) and is currently living with her grandparents to help them with their horses, but I am concerned about the effects this has on her younger brothers, especially the 3 yr old. How do I handle this with all of them and do I question the older boys on why they didn't tell me when it was happening? I am disgusted that she would openly engage in this activity in front of them and almost feel that she has violated them by doing so.

[margypops]

More supervision, do not leave the 3 year old with them,talking to them all about inappropiate behavior may be good,The older one is not allowed to bring a bf into the house,  be aware this kind of behavior does happen and you are the ones that control the situation.the younger child should be not be left with them even if you have to get a baby sitter.

[worriedmomof3yrold]

There is supervision, but I just never imagined they'd do this with a room full of other kids. Our living room is downstairs and our kitchen is upstairs because the house is built on the side of a hill. The only times they would be left with just the kids in there was when I'd be cooking dinner or cleaning upstairs. Who thinks their kids will do something like that, especially when no one else is telling you what is going on? Regardless, she is not living in the house anymore and won't be trusted when she visits. If I'm upstairs, she's upstairs. The boys will not be allowed to have girlfriends inside the house unless I am in the room the whole time. I would have stopped this from happening again had I known it happened just once. So much for trusting your children to make good decisions...it's not like this is modeled behavior.

[margypops]

May I ask how old the boys are that will not be allowed girlfriends in the house ?

[worriedmomof3yrold]

The boys are 14 and 13. They can't date yet. I'm just saying.