It will have no effect on a future move to the UK.
As larrabee said, it would only be fraud if you entered the US as a visitor, claimed you were going back to the U.K. after the wedding, but then did not take your flight home and applied to switch status to a US spousal visa/green card from within the US... because you would have come to the US as a visitor under false pretences.
There is nothing wrong with marrying in the US as a visitor, then returning to the UK to live, with your spouse moving to the U.K. as well.
If then several years later, you choose to move to the US by applying for a spousal visa at the US Embassy in London, that will be a completely separate situation and will have no connection to you getting married in the US when you were a visitor.
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