said I’d be willing for him to move in with me on the basis he is fully aware chores are to be shared and he pulls his weight. If that goes well then down the line, I’d consider looking at buying somewhere. He says he is going to think about it…
He's going to think about it ... ?
Consider the possibility of perhaps thinking about pulling his weight?
Here is a forecast, OP. This is what is going to happen:
He'll be on best guest behaviour, because his goal is to get himself permanently under your roof.
He'll be treading very carefully.
Because you've now basically promised him that if he does this, he's in.
A few months / years down the line, he'll move in with you.
For a while he might behave himself. To secure his position.
And then ... It will start.
And you'll be here, OP, sadly typing that you don't understand what's happened, where it's all gone wrong, why he's behaving like this ...?
Here's the answer ready for you to take away and look at:
Because this is his true nature.
What he's really like when the mask's off because he feels secure that he's got so far into it that extricating him will be incredibly difficult.
And if you marry, you can wave goodbye to house, money, pension.
Think of this post like a time travel glimpse into your future if you do that.