Dating sister's ex

[LoveFridaynight]

It finally happened. I have 2 DDs 18 and 16. 17 year old has been out with a few different boys in the last couple of years, which is fine. 16 year old has never had a boyfriend.
One of DDs ex boyfriend is on the same course as my youngest. They became very friendly and he's now asked her out. DD1 is fuming even though they were never serious.
I get it though. You don't date your sisters ex. I'm not being unreasonable to think that am I? I feel for my youngest DD. She's autistic and struggles socially so she's thrilled to be asked out but why him? He knows they are sisters so why ask her out anyway.
I feel I should tell youngest to turn him down. Am I being unreasonable to say you don't date your sisters ex?

My relative’s MIL married her sister’s ex! If they weren’t serious, I would keep out of it.

YABU. The relationship was never serious and if your youngest daughter likes him, he's a good kid, and it's age appropriate then there's no reason she shouldn't have this experience. Especially if she's autistic, it won't come easy for her and experience is valuable for her.

If it was DD1s ex fiance or husband and they were in their 30s then sure, "don't date your sisters ex" is good advice.

“they were never serious”… what does that mean in practice?

how well do your DDs usually get on?

I feel I should tell youngest to turn him down. Am I being unreasonable to say you don't date your sisters ex?

you need mumsnet to tell you that hell YES this would be unreasonable

If it wasn't serious than I would not invest any more in your child's relationships leave them to it

If they’d had an actual relationship you’d have a point, but a non serious teenage relationship shouldn’t matter in the same way.

My son got married a few weeks to his partner of 4.5 years.They started dating at 17.

Between the ages of 13-15 he dated her twin sister on and off (not identical).

Like your older daughter their (the twin and my DS) were never serious.

As it turns out DS and DIL were far more suited anyway.

I think at this age it really doesn’t matter;it’s just teenagers being teenagers.

I originally clicked on this thread thinking you were going to say your sister was dating your ex husband/kids dad which is entirely a different situation.

I’d wonder if he’s doing it as some weird power trip. Men are like that.

For me it would depend on whether the older DD and this lad had sex.

If they hadn't, and it was just a passing thing with older DD, then I would let it take its course, but keep an eye on it. Maybe he simply sees the same qualities and attributes in DD2 that he saw in DD1.

If they had slept together then I would be concerned. Is he trying to get back at DD1? Will he coerce DD2 into having sex just to spite DD1?

A conversation with your DD1 is required to get to the bottom of why she is so cross. Is she just miffed, or is there something else?

Having sex with two sisters is grim.

“Forbid” is a harsh word, but sometimes teens need guidance. A boy sleeping with two sisters is one of those occasions, IMO.

DD1 is fuming even though they were never serious.

No its not unreasonable - at this age they go through boy/girlfriends like water.

It's not advisable, but she probably has to find that out for herself. You just need to be ready to deal with the tears, whichever way they come.

(Why would you want you sister's discards anyway?)

"ex" is a big word for a short lived teenage thing

At 25 mortgage together years weird yes at 16, doesn’t really matter… I would keep out of it.

Nope! I’d try my hardest to prevent her dating him, it’s just not worth any potential fall out.

God if her sister is going to keep going through a few boys every couple years then the dating pool for little sister is getting smaller! At this age and when she’s had a few lads in those couple of years I wouldn’t class any of them as ex’s.

Don’t get involved.

At their ages unless you have concerns about her safety then no, don't intervene.

My first thought would be he wants the kudos of having dated sisters (sadly a lot of porn now fetishises this kind of thing) and/or he wants to make a statement to his ex.

I would worry that your 16yo is getting taken advantage of due to her autism. Are we sure this guy actually likes her or is he using her to get back at his ex?

DD1 and him were together for maybe 3 months. I know they had sex at least once in that time but near the end of the relationship.
This lad seems nice enough, but does have a tendency to do stupid things. He was driving with DD1 at a stupid speed and crashed his car. Luckily no-one was hurt but he was obviously showing off/ trying to impress her. DD1 said to her sister (not me) you don't know what he's like. But I don't know if she's just saying that because she's annoyed.
They usually get on pretty well. They do bicker but nothing major.
Okay seems it's okay to date your sister's ex. I'll keep out of it. Although I am going to try and find out what the you don't know what he's like comment is about.
I just worry about DD2 so much. She's so easily led and always sees the best in everyone but I also know I have to let her grow up.