Yikes, I am so confused. I think I am in the same situation.

I was told at Jomtien immigration to go out of the country and apply for the 90-day visa based on marriage and then to extend it once I was back in Thailand. I showed them my husband's passport/retirement visa and they confirmed the process. I even asked if it was better to do the guardian visa option (I have 2 kids in school), and the immigration officer told me the spouse/dependent visa was the best choice.

So here I am, in Cambodia, waiting for the e-visa to be approved. I hope this wasn't a waste of time.