hi, what is the visa called if I want to marry my thai bf and where can I find all the info about it?

unless there is a different visa I can stay for a long period of time to stay with my thai bf and our baby but I have no intention of working over there and getting a work permit as I work online. I don't wan't to get married just for the sake of a visa unless it is the only way our family can stay together!

I also understand our baby would have to be on my visa if it does not have dual nationality and I can't apply for that unless we're married? how would I go about getting him on my visa?

thanks :)