How did you jump to that conclusion???

It was a joke.

And how do you know its not his mom that's dependent on him?

That’s my feeling, too. If this was something important to him, he should have told her long ago.

This. And OP also doesn't say how far they were planning on moving. There's a huge difference between 'an hour' (or a few hours) and 'other side of the country/thousands of miles' away. I agree he should have mentioned it earlier, but it's also possible that he thought he would be okay with the distance but as D-day arrive, he realized it's a huge issue for him.

It kinda is a red flag if he prefers to be closer to his mother than his partner. At some point you've gotta live on your own.

Except I really don't feel this is an 'either or' situation? Technically if you're living with someone you're living closer to them than someone else, but that doesn't mean you need to cut all ties with your parents and move outside visiting distance.

There is nothing wrong with wanting to live close to your family but it sounds like the boyfriend is just using that as an excuse because he's having cold feet about moving. It's not like they planned this a week ago. To give him the benefit of the doubt though: there is also the possibility that his mother's circumstances changed recently (health issues, etc) and that she needs support.

We have multiple ways to travel. I moved states away when I was 17. I still saw my family plenty. But uprooting your entire life for your partner’s job is tough. And sometimes people chicken out. People get scared about losing the familiar support, like Mom. I hope he had a last minute change of mind and didn’t just hold off on saying something. And if it’s just cold feet, he may follow soon after.