Um Senua, did you land upon this section by accident? The deal is most/many/some of us are in one place for 2-3 years and then may move on. Not due to a lack of longterm planning necessarily! Rather a sense of adventure, urge to see the world etc. Judge us if you will - there are obvious downs to it but our dc get to have a new and wider perspective on life, pick up new languages and be more flexible..
senua OP is going back to the UK - presumably she will have some friends and family there somewhere, so she won't be starting totally from scratch. I'd imagine her DC probably speak some English already as that is OP's mother tongue.
I'm not sure how much long term planning she can do, though. Once you start on the expat circuit, things can change quickly. OP may be talked into going on this posting as "it's only for 2-3 years", but then her DH gets offered a promotion maybe there, or in another country or back to where she's currently living. Very hard to predict. And once you've put your own career on hold, it starts to become more difficult to argue against another 2-3 years "that will really add something" to her DH's CV.
At the end of the day, you are giving precedence to DH's career and blocking your own.
Never mind all that - what about the DC? You say the secondment is only for 2-3 years. What then? Another coutry, another language, having to make new friends all over again? What's the long term plan?
Watch out for the "loss of self" aspect. It's a biggie. There are also other practical considerations like pensions etc. that will impact you, which may take on more importance if your marriage doesn't last.
At the end of the day, you are giving precedence to DH's career and blocking your own. Given that you think your marriage is already a bit rocky, you may well end up either a) resenting it or b) at best, wondering why the hell you are in this foreign country, with no friends, no career, missing your job and sense of worth and no real desire to make the move work.
I have followed my DH to the other side of the world and gave up a job I loved. Its been really tough - the fact we are happy together is the only thing that has got me through. I think the "loss of self" is really hard. That said, if you could line a job up and perhaps you have family/old friends here, it could work well and the move could be just what you need. Maybe it would make you both feel a renewed commitment to your life together?
Part of the reason DH and I moved abroad was because our marriage was struggling. As others have said, the pressure of moving and establishing yourself and your DC somewhere new is so tough. 2 years on DH and I are still together, but still confronted by the same problems.
I would secure yourself a job in the UK first before moving. (Spoken as someone who gave up a great career job to go abroad with DH - 5 years on I don't regret it, but it was difficult at the time and often caused me to feel resentment towards him).
That's the dilemma at the moment. DH has been offered a secondment abroad for 2-3 years. If I were to go with him, I'd have to quit my job, though I could possibly freelance in my field from abroad. Have 2 DC who are settled at school and preschool here.
The twist to the tale is that we actually live abroad (Europe) in DH's country, have been here for a decade or so, DCs born here. The post 'abroad' would actually be back to the UK, where I'm from. DH can't understand why I wouldn't jump at the chance to go there.
However, our marriage has been somewhat rocky lately and one of the things that keeps me going is the thought that at least I have a job and could at least support myself and the DCs if we were split up.