Get a work permit if you work. If you're retired, get a retirement visa.
The benefit to the girl is obvious. To you there is no benefit. Work permit or retirement is much better.
You don't want your staying here in a temperamental Thai ladies hands.
If you want her to go to your country, then that is entirely different. But even then I would have a think. Not many Thai women settle overseas. Most return pretty quickly because they are naturally shy and struggle to make friends or acclimatise/language barriers.