TLDR - I'd love DP and DSC to live with me, he keeps changing goalposts, AITA for getting impatient?
For some background context, I've been with DP for 18 months, we just click and never argue. We're both in mid/late thirties, I own my 3bed house, he rents his 2bed flat.
During the first lockdown LY he lived at mine whilst furloughed and only went back to his flat for his nights with his kids. Whilst they knew about me, I didn't meet them until 9 months in, but we get on really well (DSD (12) always asking my advice on things and sending me tiktoks and DSS (7) has already told his dad that he should marry me!). My only dependent is an elderly labrador who they all dote on! We will not have any further facility as he's had the snip.
He has the kids 2 nights a week and every other weekend, though his mum often whisks DSD away to hers (she lowkey threatened me not to get in the way of their relationship the first time we met!).
The kids currently share a small single room on bunkbeds and preteen DSD is already getting ratty with being woken up or pestered by her noisy 7yr old brother. DP already struggles to afford the rent on his own, so can't afford to get them their own space, and can't afford Internet, and it's dreading costs increasing as they get older.
In autumn, I got a lodger in as I was struggling to make ends meet after several costly vet trips had to go on credit. I included DP in the lodger selection process and he and kids get on well with her. we always knew she'd be gone by spring (buying a house) and he said we'd then spend summer getting my house ready for family and then he'd move in so I wouldn't need to get anyone else in. He also said at Xmas that it'd be the last one in his flat.
Lodger has now given me notice to move out at the start of May, so I figured it'd happen organically - they'd stay here more and more frequently and prob move before new school year begins to save disruption.
DP suddenly said last night we'd spend this year getting house ready and they'll now move in summer next year now. All the house needs is a change of decor in what would be the kids rooms to make it more personal to them which we could easily do on a weekend. He'd bring his current furniture, and to reassure him (/MIL) I even suggested signing an agreement that anything I/we buy for the kids would go with him in the unlikely event of it all going wrong so he's not left in trouble.
I'll pay the mortgage, he can just pay utilities, meaning he'll be about £700 a month better off and so could finally start putting something into his pension or savings for kids (who plan to go to uni). I've even said I'd give him a few months where I'd cover everything on my own so he can get an old loan cleared, as I've pretty much cleared mine now thanks to lodgers rent.
I can afford to go for 6 months without having someone here, but not comfortably and if this isn't happening until next summer I'll likely have to get another lodger in, which means the decor, staying round etc will all get pushed back too. frankly I don't want to keep living like i did in my 20s tiptoeing round lodgers, as its really unsettling and my house doesn't feel like a home like it did when he stayed during furlough. It feels like we've gone backwards and it's breaking my heart when he delays things.
I just can't understand why it needs to wait another 15-18 months. We all get on really well, our relationship is ready to progress, it'd make more sense for our bank balances and the kids are eager as they'd get their own space and have Internet etc so they can keep up with their peers and he'd have a better childcare set up with me being able to support when he's at work.
The only thing I can think of is his mum putting him off. She's never had a long term relationship herself (had him at 15 and raised him alone) and she gets possessive of her grandkids as she currently looks after them if he's at work. She is venomous about his ex and very controlling, I do worry about the impact this has on him /the kids.
Sorry for long post, I just needed to offload and get some other opinions as I'm not sleeping for over thinking. Am I the a-hole? Is 18m - 2yrs too soon to move in when there's kids involved? How can I approach this with him?