Well, in what way did he share it? Maybe he was testing the waters to see if you'd say 'I'd also like to move there one day' or 'wow that sounds fun, count me in if you'd like company'.
4 dates in is very early days so I wouldn't stress just yet.
I will tell you my story though just jncaee it ever becomes relevant. So...my first partner, if you can call him that as tbh I never knew where i stood with him. I was young and naive. All I knew was I adored him and we spent most weekends together. Well, he would always mention wanting to move to America. And it made me feel... 'not enough'. He wouldn't say 'we' he'd say 'i'. As if he didn't see me as part of his future.
(I'm adding this next bit as it will become relevant) He'd also do other like talk about his ex as if she was the one that got away (even though he would also slag her off at any given opportunity too). And he would say things to compare me with other women thar weren't nice. Like 'why can't you dress like her' ect...
There is something called narcissistic triangulation - which is when abusive men use other people or even, PLACES to make you feel 'not enough'. To knock you of balance and leave you wondering where you stand with them. Commonly they use exs or people on the TV. But places are a possibility too.
Eventually I realised he was a selfish jerk amd not capable of caring for me the way I did him so i left him. He actually, married an American women. And years later we had a brief conversation where - he tried to triangulate me AGAINST HER!
And I realised then, she is going through now, exactly what I was all those years ago. He's likely saying to her he misses home all the time.
Because its not about the person or the place - some people are just never happy with who is infront of them or where they are. Because they don't want to be. They don't have it in them. They always want something else. And that's not your fault.
So, just be aware thar things like this can become apparent. And if they do then, run. Because its not thar you are lacking anything. It's that THEY are.
Now I hope he's not similar to my ex but just ve aware if you continue to date and he continues to say these things.
Also be aware that...he may even be hinting that you guys aren't going to last.
And he's too wimpy to say.
Just take things slow going forwards. Hopefully it'll all work out. Maybe one day you'll be in America with him thinking back to this :)