But that is quite clearly not true because that is exactly what you want to do to your husband- you want him to return to the UK when he is adamantly against it. You are being a bit hypocritical, really- essentially you feel it is ok for him to be unhappy in the UK but if he won’t agree to move from Spain then he is being awful and trapping you there.
I understand why you are upset, but the real issue is that you can’t both get what you want and stay together. Therefore, you need to make a choice, bearing in mind the consequences of each option. You won’t get anywhere pretending that he is in the wrong and behaving terribly by not giving in to your wishes because you’d never put him in the same position, when that is patently not the case. You absolutely would, in a heartbeat, if what you have written here is any indication. You know it, he knows it, pretending otherwise just makes you appear disingenuous and as though you are attempting to be emotionally manipulative. It won’t help. I know that sounds harsh, but it is also a reflection of what you have said.
Neither of you are wrong- it’s absolutely understandable that you want to come back to the UK for all the reasons you have outlined and it is also entirely reasonable that your DH wants to stay where you have settled and he is happy. If you are to remain married, then one of you has to live somewhere you don’t want to, and that person may well be miserable if they cannot find a way to come to terms with the situation- however unpalatable you find that. I don’t think he is trapping you, anymore than you would be trapping him. It’s just an unfortunate situation where two partners want different things in a situation where there is no compromise.
I agree you may need one last discussion, with your cards on the table- but don’t threaten anything you won’t actually carry out in an attempt to get your own way- and remember you need to listen to him too. Then you need to accept his decision, just as he will need to respect yours. If your DH does not want to return to the UK then the only question is which do you want more- to remain married and living in Spain with your family, or return home (possibly alone) having ended your marriage?