I don't think you are over reacting at all. I think he's sticking his head in the sand and NOT reacting which is even worse than if you were over reacting!!!!

I'm having trouble wrapping my head around what's going on with this kid. 13 means she should be thinking about boys and getting to that interested stage. The fact that she's 13 and sexually active with both sexes makes me wonder if this child wouldn't benefit from some counseling very, very soon. I'm afraid she's going to get pregnant or worse. She's causing harm to her best friend. Is her best friend mature enough to be engaging in these activities?? I'm thinking a call to her mom might be in order. And maybe even the school. It's normal for kids to be interested in sex at this age but geeze, I am not sure what is up with this kid??
Is she more developed than her classmates? Something is up. She def needs some help. I always heard the saying that if she's not sitting in her daddy's lap she'll be sitting in someone else's all her life. She's got some issues.

My DH would blow a gasket if there was a note like that. What planet does your DH live on that he thinks this behavior is normal/ok/minimized?

I agree with mommagain about a phone call to the other girls mom. If your DH won't do anything I'm willing to be the other mom will stop the sleepovers/not allow them at your house either.

I don't think you are over-reacting. However, as an educator, I can tell you that it is normal (although unsettling) for 13 year-old's these day to be curious about their sexuality. However, as with all issues, they need the proper guidance from the adults and mentors they have in their life.

You desperately need to have another conversation about this with your husband. What do you "need" to have happen here? Do you need her to stop having sleep overs with her in the home you share? If so why? Share the note with him? Ask him what his suggestions are? Why does he feel so strongly against addressing the issue with his daughter? What life and future does he want for her? If he is unwilling to budge on addressing the issue with her, then a possible solution is to have her spend the night at her friends house if there is going to be no parental action. That way, your younger child at least won't be exposed to that behavior. At the very least, I would say that she needs some serious guidance about sex, STD's, and why she feels she needs to connect with people (male or female) in this way. It may stem from a deeper issue of self-esteem etc. And she needs to understand what is appropriate in front of younger and very impressionable children. Regardless of a difficult past, all children need to know where the boundaries lay. Without them, they will continue to explore until someone (or life) stops them.

Hope the comments help.

Your DH is ok with this?!?!

No way I would raise MY child around this dysfunction.

Maybe you should put a big in the other mothers ear ~ and see how that develops.

Sexually active at 13 ~ is concerning. Kids obviously are starting way faster than my generation. Sure I had a bf but ... Heavy petting was what was going on. Not sex !

Sure kids are going to be curious and that might be a reason he is not objecting but 13 !!! I thought kids: young adults get curious in college bound years. He could be ignoring because he has the attitude " Not my kid" ~ he is also worried about how he got this information ~ on his mind he might think. You invaded her privacy. Which is a crock of $hit. Afraid to confront is a ridiculous way to live ~ sweeping it under the rug.

A couple of years ago my SD was caught having second in her bf's car on school property by a teacher/coach. ( at the time she was grounded n forbidden to see him) she had a school project ~ where the kids had to interview a teacher. My bd was in the same class so I knew it to be true. They called me for a ride home ~ I waited at school for the both of them ~ my bd n I were in the car waiting for her. She came out ~ n we went home. Next day SD stayed home from school ~ she was sick. Next day went to school ~ school must have pulled kids in for questioning. Next day she was spoken to about said incident by school. Next day ~ the school called the mother who ~ then came over to my house to inform me. WTF !!! I had to call my bf n inform him. Had him pull off the road from his delivery to tell him. The rage in his voice ~ OMG. He was furious ~ calmed him down. BM called me later than night n asked me not to let SD know that I knew. R U eff'ing kidding me. All of this was swept under the carpet n to never be spoken of again. You people have got to be crazy < that's how you want to handle this. Poor little SD is mortified that everyone knows. No you just gave her every reason to believe her actions were reasonable. Not on my watch. Spoke to her ~ saying is that really how you want to be remembered ?? Shouldn't you have a little more respect for yourself. Your bf just completely disrespected you.

Parents just are eff'ed up !!! How in the world is that ignored.

Supporting and ignoring are clearly 2 different thing ~ tell that to Future Grandpa !!

You have your own BD10 to worry about! This would not be happening in my house. We go through the rounds every year with BM trying to get DH to let SD13 stay home alone with my BS13 for Thanksgiving (1 week) and Christmas holidays (2 weeks). I tell DH no way he had better take off some days with her and I'm not babysitting her. Number 1 kids are very curious at that age(even though my son can't stand her I'm not taking that chance). Number 2 she sits all google eyed when my son is around . . .makes me sick. She takes pics of him when he's not looking and sends them to her friends (caught this one snooping on her phone when I noticied her snapping a pic). I'm sure at her school he's her boyfriend . . .just sick. THIS WOULD NOT BE GOING ON IN MY HOUSE!

I don't think you are over-reacting at all!!! 13 is way too young to be sexually active regardless of whether or not she has homosexual or bisexual feelings. I have nothing against those who are LGBT. My biggest concern with this whole situation is your BD10!!!! I would be concerned with the kind of people that SD13 is bringing into the house. Don't leave BD10 home alone with SD13 no matter what! I know this may be of some inconvenience at times, but if she has grandparents to go to or some friend you can trust 150%, that is where I would take BD10 on any school holidays and such. With this kind of lifestyle, I would be worried about them making out in front of BD10, or worse, some of these "friends" of SD13 touching BD10 in inappropriate ways. I know it is not something anyone of us wants to think about it, but sexual abuse by "peers" just a little older is a very real problem.

Your DH needs to get his head out of the sand! This girl needs help! What kind of stuff has this child gone through that is triggering this behavior? Typically this kind of sexually promiscuous behavior is related to some sort of abuse at some point in one's life. The girl needs counseling...this needs to be nipped in the bud, or she is likely to end up drinking, doing drugs, or "on the pole" as well. I know it is taking things to the extreme, but statics point to this. DH will be an early grandpa, or be dealing with a drunk 15 year old having her rushed to the ER for alcohol poisoning, or worse. This is NOT something DH should be ignoring!

If he would not allow a boy to sleep over with her in your home, it would also be imprudent (read: stupid) to allow this girlfriend to spend the night. There is a huge difference between "support" and 'turning a blind eye because the thought of my daughter having sex makes me uncomfortable so I'll ignore it'.

Classic guilty daddy reaction.

"I can't discipline my kid because I might lose him/her"
"Kids will turn out the way they turn out" (i.e. it is what it is)
"It won't make a difference; her mom will just let her do what she wants anyway"
"The courts won't let me parent my child"
"They're JUST KIDS!"
"They're innocent as the wind driven snow"
"They're too old to change now"
"I don't want to make waves with the BM"