When did you let your teens spend the night with the girlfriend/boyfriend?

Given that both of them are very emotional, your DS has OCD and is very stressy, this could go wrong very quickly and easily.

I read a thread earlier where the OPs 14 year old daughter became pregnant by her 15 year old boyfriend. They very quickly broke up, the girl was left contemplating single motherhood or an abortion.
So you and the gf's parents need to speak to your child about the importance of contraception every time!

Why does the relationship ‘have to be kept as light as possible’?

Hhm. 2 months in and they're already arguing. I would be wary of setting a precedent. She sleeps over after two months, they break up, he gets a new gf, do you want a procession of girls sleeping over and is this how you should be helping da navigate healthy relationships? But then I'm old, I wasn't allowed ex to sleep over until we I was coking back from Uni holidays and even then his mom and my dad talked about it 😂 twas this century I swear

At 17 I don’t think there’s much you can do about it. I wouldn’t have it in my own home but you can’t control what the gf’s mum and dad allow. You could try and speak to the parents and explain your concerns and see if they would take it off the table but you prob won’t have any joy.

Honestly yes I think you're being too protective. At 17 he needs to learn by experience and living, how do you think he will develop emotional maturity otherwise? It won't magically come just by waiting for the months and years to go by, you need life experience and he's old enough.

I’d be fine over 16 if in a relationship…. I’d not be keen on lots of casual sleepovers with different people.

DH feels very differently though so we’ll be needing to come to some kind of agreement when DC are that age.

I had my bf sleeping over from 17.

You’re absolutely right to say no. Especially only two months into the relationship.
Sleeping over at that age is too intense and the relationship needs to be kept as light as possible (I fully understand the intensity of teen relationships, my son is 6 months in with his first gf).
It would be a no from me until they’re 18, have finished school and are in a long-term relationship. You’re not an awful parent and all the other parents don’t allow it!

I don't know what difference 17 is meant to make compared to 16? Honestly I'd just say 6th form. People feel different things about this though. I wasn't allowed to share a room with DH until when we visited each other's parents until we got engaged age 22 which was slightly ridiculous given we were living together in our own house at uni!

My son had his first girlfriend at 15. I’m sure they had sex before, but I knew her mother and we agreed that they couldn’t share a room til 16. They went away for a trip abroad at 15 with her father and they stayed in separate rooms.
Once they were 16 they could share a room. We talked about birth control and consent etc. They broke up after dating for a couple years.

My own DC are still young, but when I was 15 I had a lovely boyfriend a year older, my parents and his parents were fine with me sleeping over his from when I turned 16. I think they were all very much of the opinion that we’d do it regardless of whether i was staying over or not 🤣 and we were obviously both legal age (UK) x

Why 17? The legal age is 16. They will just do it anyway if they haven’t already. YABU to try and control his actions and emotions at this age, these are his choices to make and mistakes to deal with.

17 is fine in my book. They will have sex when they want to and a bedroom is not needed. I think I prefer to look ahead and think about how I want them to be able to manage their own relationships, home works, study/work etc. it’s a short time to uni and I think they are better having freedom before the get it all in one go. I would be more worried about their emotional maturity, ability to be kind and to be able to take care of each other and them selves.

After they'd been away at University for me.

But I think it is more to do with length of relationship and maturity of both of them as individuals.