Newbian- YYY, a lot of what is on this thread is not only exaggeration but impressions gleaned from movies and tv.
Nevertheless, as someone who has found herself with very limited options following divorce, I would advise caution. There are no medals to be won for doing bold deeds out of a misguided desire to appear fair to someone who has very little to lose by moving.
If the OP has relatives who live close by (not ILs but her own family) her life could be relatively fine if she were to find herself in a relationship that went pear shaped, or if she were to divorce. However, the misery of all that would be magnified by distance from all moral and practical help if she has nobody nearby. There are serious financial side effects to having nobody available to lean on for free if you are a single mother trying to find a job after divorce.
I have come to believe as a result of my own experiences that it is really smart for mothers to weight availability of practical support, a friendly smile from a familiar face, a cup of tea in a kitchen where you have sat a thousand times, etc. far more than factors like income or availability of nearby ski slopes, etc.
Somebody upthread asked the OP if she was familiar with her DH in his own home turf with his old friends, in his old family dynamic, with the warning that a DH can look altogether different in those conditions. I think this was an excellent point. People can revert to old habits of mind, old relationship dynamics can resurface, and you might find yourself looking at your own husband and asking yourself, 'Who is this man?'
I would like to add that the power balance shifts when one person is at home and the other is new to the country. Is this a factor in your H's desire to return to the US? When you are there, you will depend on him for a huge amount of support in acclimatising, finding a social network, translating for you, explaining customs and mores to you - you will be in a teacher-student relationship in some ways. This can affect a relationship.
How likely is your relationship to be seriously stressed by the changes a move would entail? Only you can answer this central question. If your gut is saying stay, then I recommend staying, and perhaps finding some other way to satisfy whatever desire your H has to be in the US, whether that means connecting with US expats more frequently, travel to the US, more meaningful relationship with the UK through involvement in UK culture, sport, volunteering, etc.
If his UK job is not giving him joy, would another UK job help?