To not want to live with DP

Don't let him downplay the impact of living with teens/young adults! They do require a lot of energy, thought and care to raise/manage relationship with/feed - which will fall on you by virtue of living with them and inevitably there are hiccus along the way, not to mention managing a huge transition such as moving in together. Might even be easier with younger children in many respects as they are more adaptable.

YANBU
Only you can decide if you want to live with someone. Sounds like you'd be better with your own houses. You could have one ot two nights a week that you stay over at each other's.

The weekends away will come towards you. If he has two teens the oldest must be what, 15 at least? So it's not that long before they can be left overnight.

I think you need to resist this idea that you are being selfish. The current set up works for the kids as well as for you. Teenage years can be complicated and stressful - much easier for the kids not to have to cope with step parent and step siblings on top. Great that you have the financial resources to give them freedom from that. Especially with his teens who don't even choose to stay with each other so would be very unlikely to enjoy sharing space with a step.

Imagine if all it took to be a good mother in people’s eyes was to be in the vicinity of one’s children 😂

There’s no way I’d agree to this! As others have said, just say you don’t think it’s a good time to blend the families right now but you can revisit it again at some point.

I think you can also point out that his kids probably don’t want you there either. Assuming they’re old enough to be home alone, they’re very unlikely to appreciate you suddenly being there all the time knowing what they’re doing. If it was me I’d phrase it that I wanted my own space, but I also very much wanted a good relationship with his children and suddenly invading their space where previously they had been given independence was likely to create resentment. You are definitely allowed to say you want your down time on his own, but I’d pre-empt any suggestions they you don’t like his kids by making it clear that this is best for them too.

That's not a good dad, that's just a dad

👍🏻

I don't think anyone will argue with me when I say that typically, men benefit far more from a blended family set up than women do.
Nah.

I honestly can't see what you (or your own child) would be getting out of this tbh. You'd lose your own home, time alone with just your own child, time for yourself and you'd end up parenting children who aren't yours, and doing childcare while their dad goes to work! I bet your own child would suffer as a result.
I don't see this arrangement as beneficial to anyone - his kids might not even want this either!
Blending families is messy - I say keep your finances and home separate and protect your own and your child's home and lifestyle.

You do realise that moving in with him would inevitably mean that you would never have any alone time and would have to explain that you wanted to go away for a few days?

All that extra shopping, laundry, tidying, housework?

Only someone batshit would consider doing this to their own children and themselves.

Disaster.

That’s understandable, I don’t think I’d be up for that either. It’s a lot of upheaval for your DC too. Why not plan to live together in 2-3 years when all the DC are older and maybe moved out or at least are adults and don’t need much parenting

I like this answer!

Why should your kid live with other kids they don’t know? Blended families aren’t easy. Just say the current arrangement works best for you and your kid.

You said: "since he has had his DC 100% of the time, I just don't want to live with him."
I wouldn't even bother asking if this is unreasonable (it's not). You know what you feel and want - go with this. Yes, you have permission.

‘Default parent’ as @user1471538283 said might be a better phrase

I think as well saying that whilst you love / like his children a lot you’re worried about forming a ‘step-mum’ type relationship with them given he’s out of the house a lot and you’re in. I think it can be important to address the issue directly and matter of fact-ly

'I feel like I need to be so careful with what I say though as he’s a good dad having them all the time'

That's not a good dad, that's just a dad.

You're being extremely sensible here and you're absolutely right to be thinking ahead about the impact on you and your kid. Moving in together would be madness

Going from 2 to 5 people at home is a huge leap. The bit I most loved raising my DS alone was that we could just go and do things without having to consider anyone else and it was cheaper. We would often go for dinner and the cinema because we didn't need to rush back. Or spend the whole day out rolling in late. Or day trips. Even quick little holidays.

The thought of having to factor in 3 others and all the extra work turns me cold. Before you know it you will be the default parent.

OP blending families needs to be really carefully considered. I’ve been with my partner over 5 years we still live separately. It’s only after 5 years of holidays together and a very specific point in both our DCs lives we are now buying a house together. My DD will be finishing GCSEs this summer, his DS is at the end of his second year at University and we can afford something expansive so they do not just have enough space, we can have space and there is enough social space for when they want to have friends. So do not rush into anything. Keep it as it is for now. You have kids of different sexes, be very very careful.

Definitely don’t do it. I moved in with my partner 4 years ago when we had 5 out of 14 nights childfree and it was lovely. Fast forward a year, his kids live with us full time and their mum is a piece of shit who says shell have them 1 night a fortnight but it rarely materialises… so I never have childfree time now, and we can never plan something for just us two unless we rope in the grandparents (but they do a lot during the week before and after school so don’t want to put on them even more!)

I really miss what we had. I’m not happy in this current set up and often resent the step children even though none of this is their fault. next weekend is Easter and I’m personally childfree Thurs-mon but obviously not childfree at all because the sc are still gunna be here!!!

It’s still a responsibility and how do you know that everything related to the kids won’t end up falling to you ?
shopping cooking cleaning ?
is he looking to have them both ALL the time maybe ?

That would be a massive no to me. I also am not sure I would find much in common with someone that didn’t want. Life beyond kids

I’d word it as now your dc is grown up and you have free time you don’t see the need or what for more responsibility .
It’s like having more kids would I you want those?
You can like people and you can like other peoples animals it doesn’t mean you want to live with them or care for them .

He will know fine well the only person benefiting from living together is him.

Ive down the step parenting and was damn good at it .I would never do it again though .