Long distance relationship and deciding who moves where?

[Freeshavocado]

Sorry this is probably going to be long and rambly, I'm not quite sure exactly what I'm asking but feel like I need to write all this down somewhere and get some perspective as I think I'm overthinking!!
Me and DP have been together for nearly 2 years, this whole time we have been in a long distance relationship but only 90 miles so we manage to see each other most weekends. Obviously we're coming to the point where we want to take the next step in our relationship and move in together but here lies the problem.
Since day 1 the plan has always been for me to move over to him, this is because it's much easier for me to move jobs (or so I thought, but I'll get to that in a minute) whereas DP works for one of only 2 firms he could work for north of Birmingham, with the other firm being based directly over the road.
We've both been happy with this plan as I/we both love where he lives and could picture our lives there, with me even beginning to start making friends over there.
Since we met, DP has never completely loved his job but hoped that an opportunity arising this year would change that. In some ways it has, he's had a promotion and 3 pay rises in quick succession but the opportunity has also made him realise how bad the company are to work for and how he can't stay there forever (I could make a whole thread in itself about the companies inadequacies!).
Wanting to stay living where he is now he applied for a job at the other firm over the road where he was offered it but for a lot less money, less than before any of his pay rises, and there were a few other reasons why he couldn't take it.
That leads us to the situation we're in now, DP is desperately looking for a new job but ,without trying to be outing, the vast majority are located in one county down south which is a 3 1/2 - 5 hour drive from where I live now. I've known him moving down there has been a possibility all along and I've been more than willing to make the move with him if I have too, until now.
I've been looking for jobs for myself around where DP will potentially be getting a job and there is NOTHING. I have a specialism in my field which not many firms offer but it turns out NO firms in the county have a department in my specialism (2 firms near where he lives currently do so I had options). This means if we both move I'm going to have to give up everything I've learnt in my career (I've trained in this specialism since day 1) and effectively go back to square one in some ways.
DPs career is much more unusual therefore for him to stay living where he is/move to where I am (his hometown) he would need a complete career change, whereas I guess mine is just a bit of a detour?
I was more than happy to make the move and take a new job (despite loving my current firm) but knowing that I'm going to have to give up my specialism is making me not want to do it anymore. How on earth do we decide who is going to change career??
I've not spoken to DP about any of this so far as a) he is currently abroad with work and b) the moment he knows I'm not sure about moving he will get a job in a new career near where I live now as he will just do anything to make me happy!
Sorry really not sure what my questions but just wondering how others worked round this I guess?

There is no right answer here, but you both have to be happy with your life choices for the relationship to work, and that means both finding a job that you enjoy. Anything else will just breed resentment in the long run.

Is there anywhere else you could move that would have something for both of you? Even if further away? Could you find a middle ground and commute for a few years to test the waters on living together.

My dh and I were (very) long distance when we were dating- an 11 hour flight away. I chose to move to him because I preferred his country to my home country and because my career was very portable (and really I had much better opportunities here than at home). The immigration process was also easier. But there’s no way I would have done it if it meant giving up my career, which I love.

But especially when you have no children, a longer commute is very doable. I commute 3 hours now even with 2 small children. If you could do that for a time, it would allow you to see how living together works without either of you sacrificing your careers. If it’s really meant to be, you’ll be able to find a way in time.

Thank you so much for taking the time to reply even writing all that out has helped me clear my head a bit.
I know we will end up resenting each other if one of us has to change careers which is why I'm desperate to make it work.
There are a couple of other areas DP could get a job in but they are just small towns so not sure how well I would find work, I just hate the limbo of not knowing where I could potentially be living in 6 months I'm a massive planner and hate not knowing what's going on!!
I'm worried about moving too far away from my hometown as DP works away a lot e.g. between now and June he is doing 3 weeks home, 2 weeks away then repeat (if you knew his job it would make much more sense but I bloody forgot to name change and know friends are on here!!) so I'm worried about getting lonely and hating it even more when he's away, at least being 3 1/2 hours away I can come home for the weekend quite easily.
Also thinking way into the future it will break my mum being so far from grandchildren, I know I'm probably getting way ahead of myself though!!
Hopefully once DP finds a job we will be able to find somewhere we can both commute from although I've heard horror stories about commuting through Oxfordshire (where all the jobs are)!!.