That's a tough one. DS1 had a GF from the age of 15 (she was about five months younger). We had strict rules about no sleepovers. Her parents didn't. Our deal was that we'd take her home when she was at ours and they'd bring DS1 home when he was at theirs for curfew time and only on non-school nights.
That worked for a while. Then we got a phonecall from DS1 and GF's mother saying could he stay there as GF's parents really were enjoying their weekend and had had a drink and they'd make sure he was sleeping on his own etc etc. We both said absolutely not, we are picking you up now. And off DH went to pick him up. We did this from then onwards.
We honestly didn't care that her parents didn't care - we did care about not condoning or enabling sex below the age of consent. Coz if the shit ever hits the fan, the boy is far more likely to get in trouble than the girl (have witnessed this though thankfully not with my own).
Once she turned 16 we allowed sleepovers on non-school nights that were pre-arranged with us.
Now clearly you have your own reasons for not wanting sleepovers at his age and I agree with PP, it's your house - your rules.
We can only ever exert imperfect control over our teenagers though - unless you are willing to physically drag him out of his girlfriend's home that is. So generally speaking, how does he behave?
Is he
- obeying the spirit of the rules
- secretly defiant
- openly disobedient or
- out of control?
I'd put this one at openly disobedient and would repeat your rule to him. No arguing about it - just inform him your are disappointed that he broke the rule, that the rule remains in place, restate the rule and inform him that you expect him to stick to it.
However much they hate it, most teens do actually internalise the rules. They try to get around them but our rules do exert a considerable influence. Your parenting until this point has made that happen.
IMHO the worst thing right now would be to cave in and get rid of the rule immediately (or ever). If you are willing to rethink this rule at all, what I do in this situation is to ask my child to convince me why they should be allowed to do xyz and how they would make this work within the wider rules of the household (chores, school requirements, respect for other family member's needs etc).
So if you are willing, in a few days time, ask him how he would make this work for both of you, agree a new rule (maybe a later curfew, maybe a different weekend rule whatever) and then expect him to stick to it.
(If he is out of control and sticks to no rules, disrespects and/or endangers you and your family, and doesn't react to any consequences for breaking the rules, you may need professional help.)
I've just used this approach with my youngest. Asked him to put down his suggestion for a different video game time table in writing. (Our previous rule for pre-teens was game time after school until dinner on Tues and Thurs and anytime at the weekend between 10 am and 6pm; no tech whatsoever on Mon, Wed, Fri or any day after dinner.)
I'm not content with how it's going, so we will now revisit his suggested new rules (they're on the fridge) and talk about why and what I don't like about how it's working and how he would fix those things. It is a constant work in progress...
DS2 is a harder nut to crack. We've been at war over his smartphone for six weeks now. I take it off him every night because he is addicted. This drives him completely crazy and he tries different things to get me to stop (some more annoying than others). I just restate the rule and do not engage in any discussion about why I do this anymore and just tell him I expect him to respect the rule.
I didn't tell him that I was ready to give up weeks ago because I really don't need the aggro when I'm winding down for bed but it is affecting his school work so I am motivated to keep going. For the last two nights - miracles do happen - he has actually brought me his phone rather than me having to take it off him.
Not saying that this will work for you, but it may be worth a try to keep restating the rule and tell him what you expect from him without debate.