beware that not all immigration offices offer that initial 90 day visa for marriage. My local one says you have to go to an embassy outside Thailand. It might be a minority of offices.. But still. Check first, or prepare to maybe have to take a trip. Getting it before traveling would be advisable if possible.
on the positive side, you'd know beforehand if you are refused entry. Compared to already being here after a possibly long flight, only to be refused entry for whatever reason.
It would be silly to keep getting single entry tourist visa every time if you visit so often.
Look into getting a 6 month multiple entry tourist visa or if you qualify for the new 5 year DTV that would be handy too. Come and go as you please as long as the visa is still valid.
If you where married OUTSIDE Thailand, then yes, you need to get your marriage legalized through your embassy and then MfA in Thailand before you can go to ampheur and get a khor ror 22, because it doesn't apply to marriage done inside Thailand.
If you married INSIDE Thailand, you will never need, and can never get, a khor ror 22.
On the other hand, if you married OUTSIDE Thailand, you cannot get a khor ror 2, because you need a khor ror 22 for marriage registration from abroad.
But lets assume that the marriage was done INSIDE Thailand.
In that case all you need is for your Thai spouse go to the ampheur with their ID card to obtain a khor ror 2, which is the regular marriage registration document for marriage INSIDE Thailand. Cost is 20 baht. No need to legalize at an embassy or MfA for use inside Thailand.
The original rose border marriage certificate you got when you got married INSIDE Thailand is a khor ror 3.
I do this every year for 8 years in a row now.
If you married inside Thailand you need a khor ror 2. 22 is not for you then.
"Mikkel Kruse the Thai Amphoe will NOT certify a foreign marriage. Only the embassy and the MfA will" no embassy or the MfA can issue a khor ror 22. Only the ampheir can. For them to do that, you need to have married OUTSIDE THALAND. And the ampheur requires the embassy of that country and MfA of Thailand to legalize the documents first.