What I meant about my comment about being older is that I think this transition can be more difficult for someone who made the move relatively late in life
The problem is hardly your age, it sounds to me the difficulty is coming from unrealistic expectations of both your move and your marriage.
You should see and feel the reward every single day from your wife's love for you. If you're not, perhaps you should think about a few things. Not only that, but dont try to label your move as alturistic, heroic, or the like, because when youre married you do all you can for the other person, out of an overwhelming and selfless love.
Secondly, it was your choice to move. Ultimately it came down to you packing up and moving across the pond. Being an American in the UK myself yeah, I can see how you would say the standard of living is lower than that in the US. But if your career, and subsequently your paycheck, was more important than you should've stayed. If your love was more important, then you've made your decision and its a moot point.
In addition, I don't know your situation with you and your wife. I dont need to either, but you need to ask yourself a few things. Is she ignoring you completely? Not supporting you emotionally? 2/3 of Marriages end in divorce, it probably something you would want to make sure of, that it is the most powerful thing you could ever imagine, a love so deep that you could live your life in the UK happily... and probably something to have been examined before moving.
Not that you've mentioned it, but here is a little tip: there is no way to kill your marriage faster than continually playing the "I gave up everything to move here" card.