Bf asked me to move...

I have been with my bf a while now (it was complicated so wont go into the details) but he lives 200 miles away from me in the south east. He has asked me to move down there and get a place together in the new year.
The only thing making me apprehensive is leaving my mum- she hasnt met him and probably wont do either- for reasons i wont go into here. My mum is a little vulnerable and i just feel so guilty- especially as i have only recently moved back into the same area as her and this is such a huge move.
The relationship cant continue to move forward unless i make this move, it is so difficult being so far away from each other, but i feel so guilty about possibly leaving my mum.
I dont know what to do. Dont know what i was expecting here- just a rant more than anything.

My B/F lives 250 miles from me. We have been together for almost 8 years now. We spend every weekend and holidays together. Due to both of having our own businesses and my youngest son and him not getting on very well, we have just continued as we are. He may sell his business next year and if he does we will then look at getting a house together. I earn more which is why he will move to me rather than the other way round. Couldn't you just continue as you are for a bit longer maybe give your mum a chance to meet him.
It is difficult when their is such a distance.
Good luck whatever you decide to do

I find ranting good, you clear your head so you can decide on what the best possible thing to do is. You can look at this one of two ways.
1. Your mum brought you into this world so you kind of have a responisbility to look after her, especially in a vulnerable state. Plus she's never met him.
2. Your mum loves you and probably wants you to move on in your life and experience things.

But I do think it is a bit unfair of your bf to ask you to do the marathon move, couldnt you find a happy medium in the middle, so you can easily visit your mum and he can go to work and see his friends etc?