for sure but they can’t make that judgement call. If there used to be a child living with you ( or family) then they have to assume support is required. After all that’s one key reason why Thai women find a foreigner to provide some level of good financial support.
I see someone posted the UK government website link. These are your only options. There is a visa with the right to join family which includes spouse or partner. Think this is your best bet and if you have done at least 2 years of the longer term tourist visa should be easier
Depends where you live and the life style you want. Her 1600 pounds is 2000 dollars and for a single person that is fair. I pay for 2, rent an apartment, run a truck and a scooter, live in BKK, support the family and travel. We do that on 3000 dollars a month plus the odd bigger spend.