Just to compare the options between marrying in the US and in the UK:
Fiance visa to marry in the UK
- apply for fiance visa and 2 child visas. Cost £1,523 each plus £573 each if you pay for priority processing
- move to the UK
- you cannot work or study, and none of you will have free access to the NHS, so you will all need health insurance
- after 7 days residence give notice to marry
- wait at least 28 days to marry (could be extended to 70 days if your case is referred to UK immigration...hopefully won't happen with a fiance visa
- get married
- apply for another 3 visas to stay in the UK (FLR(M) visas). Cost £1033 each, plus £500 IHS surcharge each (soon to double to £1,000), plus £610 each if you want to apply in person for a same-day decision
- wait for visas to be processed (up to 8 weeks)
- receive visas... you can finally work/study and will have full access to the NHS
Total visa cost for all 3 of you
Fiance (and child) visas = £4,569 or £6,288 if you pay for priority processing
FLR(M) (and child) visas plus IHS surcharge = £4,599 or £6,429 if applying in person... but this will rise to £6,099 (or £7,929) when the IHS surcharge double
Total = anywhere from £9,168 to £14,217... and that's just the first visas, there'll be another 6 visas to pay for over the next 5 years (2 each), potentially at a cost of £3,250 or more for each visa.
Marry in the US and then apply for the spousal visa
- he flies to the US
- you get married within a couple of days
- you apply for the spousal (and child) visas. Cost £1,523 plus £600 IHS surcharge (soon to double to £1,200) for each visa
- you move to the UK
- you can work, study and use the NHS for free immediately
- no more visas for another 2.5 years
Total visa cost for all 3 of you
Spousal (and child) visas plus IHS surcharge = £6,369 (£8,169 after IHS surcharge doubles) or £8,088 if you pay for priority processing (£9,888 when IHS surcharge doubles
Total = anywhere from £6,369 to £9,888
So, by marrying in the US, you could save yourselves up to £7,848 in visa fees in the first 6 months.