To be frustrated we’ve come all this way for his daughter just to cancel

Agree; it's possible she's a bit of a selfish princess.

There is unresolved trauma between them. Might be Childhood Emotional Neglect. Look it up. And if he’s not acknowledged any problems there may have been in the family she’s unlikely to move on and seeing him might bring unpleasant memories and be triggering. Or she finds it hard that he moved on with you and it’s the ‘step mum’ thing even though you’re clearly not a step mum in that sense. It’s down to him though but clearly this has impacted you. It’s clear you shouldn’t arrange anything around her. Keep it simple let him go to see her or visa versa. He needs to acknowledge a bridge needs building first. Or she’ll continue to show, what I’d describe as, contempt. We all make mistakes as parents. None of us is perfect, but you can do repair work. But it needs to start with him taking responsibility. Children do not behave like this for no reason.

Given that he last saw her in 2022 when she came to the UK, doesn’t sound like he is that bothered about seeing her so she probably has the same attitude towards him. Sounds like he has been a crap parent tbh.

I think it’s her that doesn’t want a relationship, he’s making all the effort and she’s doing nothing but making excuses not to spend time with him and he’s still giving her money every month. If he wants to spend time with her then stop the money, I think she’ll be breaking his door down in no time.

This is the kind of thing my sibling used to do to our father. He had done nothing wrong: my sibling was just a vile individual who got off on power plays like this while still happily taking his money.

Well, she’s happy taking his money ?

They certainly don’t sound close. Do you have any evidence at all that they are close? That they message all the time? Or that she messages?

I think he'll just have to have an honest conversation with her and try to repair whatever hurts she reveals.

I’d be more concerned with his views on the Russia/ Ukraine war tbh and his son currently living in Moscow? Oligarch?

It's clearly completely unacceptable of her. She had an opportunity in the last 9 months to say "I rather not" and didn't. She obviously doesn't think the same way of him than he thinks of her, for whatever reason and however hurtful that may be.

Divorce damages children. Exs tend to poison children and she sounds like a poisoned child, considering he's going out of his way sending money to a 24 year old... 😵‍💫 she's no feelings for him but is too cowardly, or hasn't even thought about it enough, to communicate her negativity to her father in a civilised manner. Whatever it is, it's very kind of you to feel for him. If he's wise he'll eventually realise you can't force a relationship that doesn't exist, or ever did. It's harsh but most people live in realities that don't exist rater than repare the reality they got themselves into. Good luck to you both though.

Perhaps he insisted on the visit not picking up on cues that she wasn’t enthusiastic?

IMO I think it’s best if OP keeps out of it. There may be something in his past which he may not be permitted by the Russian state reveal and if he does then he puts them and himself at risk.

His daughter may know and does not want to be seen with him because that puts her at risk.

Neither her and her father can talk about this but project a facade of a relationship to avoid any revelation.

OP has been with him for five years and he hasn’t will not or cannot reveal this secret which may have something to do with daughters mother.

I’m amazed you are dating someone Russian and you’ve not really talked about the war with Ukraine!! I’d very much need to know his stance one way or another in order to be in a relationship with him!
But anyway, it does seem rude for you to have gone all that way and her not be available, I’d be thinking they can’t be that close after all? Or there’s much more to this and she has her reasons for not seeing him. However, Lisbon is one of my favourite cities so enjoy that instead!

After the lengths she went to to avoid seeing him in Russia, it’s not that surprising she’s bailed on seeing him now. At least it is a lovely city so not like you went somewhere obscure so I’d try to make the most of it and not get involved in anything further to do with meeting her. He must know more about why it’s like this but it’s between them and no one’s place to say whose fault it is or that he should stop sending money. Kids are rarely ‘shitty kids’ without reason and these things are complicated and one thing we do know is that OP is not going to resolve and rift between them. You’ve tried to do this nice thing. It didn’t work out, you won’t do it again and he knows where her head’s at and can reflect on that. Enjoy the rest of your break and don’t plan any more around her.

Of course it is. Her AIBU is about being frustrated that they made the plans, paid for them and now she bails.

She’s rude and a flake.

“He hasn’t seen his daughter since 2022,”

OP, this stood out. The war with Ukraine started in 2022. Every Russian family I know had some sort of falling out because of this war.
I’m Russian, last time I spoke with my own parents was in 2022 as they are pro-Putin etc.

Well if he doesn’t know why his daughter isn’t bothered about seeing him then you won’t. Lisbon has lots going for it so maybe just enjoy the trip. Perhaps he should stop with the financial support. If she can gad about here, there and everywhere she obviously doesn’t need it.

That was her choice. As for the relationship with father and his daughter, it’s none of her business.

Assuming he wasn't a good father (and we don't know this), it could be pay back as another poster mentioned, or it could be that she wanted to meet up/thinks she ought to/etc. but when it comes down to it, bottles and backs out.

She is obviously avoiding him. The messaging they do sounds very superficial if she sends selfies but he has no idea what her partner does, etc., thinks she needs money but she's out every night and flitting off to Rome.

But it's also possible it's her. It might be that she has mental health issues, or her partner is controlling or something else. Doesn't sound like your DP is interested in finding out, though.

From your perspective though, there is no value in being a part of your DP's attempts to meet his DD until he's developed an actual relationship with her. For one, it's a lot of bother for you, expensive in terms of time and opportunity. And secondly, since he clearly doesn't really know her, you being there, involved in any way, is likely to impede rather than help any possibility of him actually connecting with her.

I think you need to wash your hands of it. Let your DP live in his bubble where he doesn't think there's anything wrong with his relationships with his kids, but don't be drawn into organizing your calendar (or anything else) around them. Support him if he wants to do something but don't be involved with it. Tell him he should absolutely go off and see them if he wants but you're doing X.

I would be a little bit wary about a partner who seems so oblivious, though. He may just be hiding things because he's embarrassed, but someone who is really that clueless is unlikely to be good partnership material for the long haul.

She’s rude and a flake.

All of this “there must be a reason” - well, why didn’t that reason make an appearance when the arrangements were being made?

Of course it is when she’s paid for half the holiday built around seeing this daughter where she lives.

Probably a mistake taking your kids. People always seem to think kids should accept a “blended family” and embrace it but as adults why should they? Their dad’s choice, not their’s. Stay well out of it, I would

It’s very rude of her to say she’s going to meet and then doesn’t but there’s obviously a reason.

She obviously doesn’t like him or you (maybe your kids).

How many times has he tried meeting her without you or your kids?

If she avoids meeting him, even when you aren’t there, then it’s obviously him she has a problem with.

It could be that he wasn’t that involved when they were young and she feels no need to put her life on pause for him, perhaps she even does it intentionally.

As you’ve been together 5 years, it would make sense for you to have more of a relationship with both of them.
So I would try and start messaging them (just things like happy birthday etc to begin with) and once you’re closer you can ask more about their childhood.