Getting Thai nationality is impossible but what may be done is to obtain a Thai visa for life. A document similar to a passport that allows you to remain in the kingdom indefinitely. Obviously it is beneficial to have a Thai spouse but it is not a prerequisite. I have read that only 100 of these are issued per specific announced period of a year or more from each nationality. This favours nationals of certain obscure countries because obviously countries such as usa uk India etc May have way more than 100 nationals that are interested. In order to qualify you must have lived in Thailand for several years under a type of non immigrant visa and be legal status. There are some requirements of certain merits that apply for collecting points and obviously some donations to temples or local charities would help. It is a long process but it is something that you should pursue if your goal is to actually settle in Thailand permanently.
Maybe you should consider a non IMM type of visa. Type B then You get 90 days. Needs a letter from your spouse. And needs to be applied at your Thai embassy