What should I do about my visa situation upon returning to Thailand with my Thai wife?

Appy for a 90 day visa based on marraige

In your own country

American or civilised world dating?

Just get married again 🙄

I know it is pedantic, but there is no 30 day visa on arrival for Thiland. Depending on your passport you can either get a. a 30 day visa exempt stamp (which you can extend for a further 30 days at Immigration Office for 1,900 thb), or b. purchase a non extentable 15 day visa on arrival. It you intend to visit Thailand, then you need to learn and use the correct (official) terminology.

If your marriage visa expires in May, why would you come here on Visa exempt? Kind of silly.

Either get a dummy ticket or as you are presumably travelling with your wife and have old visa explain situation. But you could get an awkward check in person who wont listen to reason.

What about re-entry permit if the marriage visa/extension thereof is operative. I would've thought the poster is probably unaware and could end up as a busted flush anyway, having to start all over again, having come in visa exempt/on a tourist visa??

Your question doesn't make sense. If you already have a visa then you would be entering Thailand on that visa, not on 30 day visa exempt. You either have a marriage visa to enter Thailand with and get an extension of that visa, or you don't have a visa and you'll enter Thailand visa exempt (not visa on arrival) and then apply for a marriage visa.

If you enter Thailand AFTER your visa or extension has already expired then you can't get a marriage extension since you won't have a marriage visa. You'll need to start over by applying for a new 90 day non-O visa based on marriage.