Partner too close to teen daughter?

Not just my own experience.

I've seen it happen many times in real life.

I've also seen many threads on here on mumsnet, where women have said that they are jealous of their stepdaughter.

Maybe the older women could grow up, and not blame their teenage stepdaughters

I have just re-read your post
sometimes they are cuddly
sometimes they hold hands
sometimes she on his lap
so my instinct tells me this is more of a you problem than a them problem

Actually it is the daughter who is jealous of the time her father spends with OP. Not the other way round.
Personally I have never seen a 19 year old woman sit on her father's knee. I have never seen a 19 year old woman walk down the street holding her Daddy' s hand. And you are trying to spin this as normal behaviour ?
I would hope nobody would begrudge a daughter having a relationship with her father. But everyone should be concerned if the relationship presents itself as so inappropriate.
I don't know what your agenda is but you are intent on normalising something that is not normal.

'She gets on well with her mum but she’s not around much , has new partner and new child . I’m very aware of this and make sure she has plenty of time with her Dad and always feels completely welcome here. I actually love her being here.'

That's what the OP said so it looks like she is considering her stepdaughter's needs. In today's society (rightly or wrongly) it's a bit strange for an adult daughter to sit on her dad's knee.

Ew, it’s giving Donald and Ivanka.

I think your own experience has given you a very warped worldview. The op is perfectly right to find this behaviour inappropriate and cringey - there is nothing bitter or resentful in her posts, just a sense of unease and rightful concern.

Honestly don't focus on whether they are right or wrong, just focus on gathering your feelings and sharing them.
Then it's up to him how to validate your feelings and he's perfectly entitled to maintain the relationship with his daughter and at that point you will be able to decide whether you can accept that or not.

Maybe the "adult" thing to do would be for the adult older woman to consider her teenage stepdaughters needs.

Instead of being jealous of her

Let's say that we all have a partner who has a 19 year old teenage daughter with another woman.

The daughter is coming round to my house. She is laughing, she is getting all my partners attention when she's there.

What does the stepmother get out of that situation. Nothing. She loses attention by the stepdaughter being around.

Of course the stepmother is going to get jealous.

The question is can you be strong enough and mature enough to overcome the jealousy. Can you also be kind and see it from the stepdaughter side. That she needs her dad's attention and lobe.

Or the other option is :

Date a man who doesn't have a teenage daughter

A lot of a young teenage womans safety and security comes from her dad.

She will be especially attached to her dad and needing comfort and security when she sees him, as her parents are split up.

I'm not undermining.

I don't agree with her that there are any concerns at all.

You can't undermine something that doesn't exist.

I think the problem is in the OP. It's her jealousy

Well basically you are saying the same thing.
For some reason you are trying to undermine OP's very legitimate concerns about the relationship between her partner and his daughter.

Or maybe it’s just a bit Donald/Ivanka Trump. It’s weird as hell.

I was really affectionate with my dad before he died, only called him once a week and very much lived my own life but when I was home I'd curl up on the sofa with him for a hug. I don't think that's in any way 'disgusting' or 'wrong' and it's a bit sad to make that judgement. The rest of it does sound like she's much too dependent on him which can't be healthy for her.

Holding hands, cuddling, sitting on his lap...it's plain weird. Would absolutely give me the ick.

What and whose boundaries are they crossing??
if they are both happy with it (and assuming there is or has been no sexual abuse) its absolutely no one else business apart from theirs.

Why I asked if dad is rich, unfortunately I know many many rich dads who, when you see them with their tall 18/19/20 yo daughters, you do a double take when they say ‘this is my daughter’.

and they are just close with nothing going on. These dads are fit and so are their daughters as many rich/ wealthy pp are. Dads take daughters designer shopping etc etc. new girlfriends would need. a very thick skin. However, 99% of those I have met, are still happily married to their wives, daughters’ mothers!

these dads are also very close to their own mum, with only the age difference a give away it is not their wives.

the girl must be scarred dad would abandon her in favour of you and your sons. She barely sees own mum. I don’t envy the young woman.

I didn't say the same thing.

I added points

You’ve already posted once. You didn’t need to say the same thing again.

Tale as old as time.

Stepmothers that I have seen are nearly always bitter and resentful of their stepdaughter. For three reasons.

1. The stepdaughter is younger and prettier.
2. The stepdaughter is a reminder of the ex wife and probably looks like her.
3. The stepdaughter is a female , who is getting the man's attention.

Just have an open honest chat with him about it. If you can't initiate that then you've got even bigger issues in your relationship.

You could just start off by saying something like how's DSD? As I've noticed she's called you for 5th time today. Were you like that with your mum at that age?

That’s weird behaviour & definitely crossing boundaries. You’ve been patient to put up with it up til now.

I’d try to address it with your DP, but if things don’t change I’d be moving on from the relationship.

Well tbh if people thought this young woman was her partner's girlfriend I would think the jealousy emotion is more about people thinking he would have a young woman as a partner rather than someone of OP's age. I don't see the jealousy being particularly of the young woman herself because OP speaks very fondly of her.
I think the weirdness of the relationship between partner and daughter far out weighs any feelings of jealousy she might feel over people assuming her partner has a young girlfriend.

Personally I’d want to hear the daughters and her DP’s version of events.
One persons needy and clingy as another's distant and aloof and all that.