How many visa extensions is too many?

I have been in Thailand on tourist visas and visa exempt entries for about 19 months of the past 2 years. I know that Im rolling the dice every time I go through Thai immigration and Im planning a long term solution, i.e. marriage in the near future.
Anyway, I would like to extend my current SETV for another month at Chaeng Wattana. In the past thirty-six5 days Ive gotten 2 visa extensions and in the past 2 years I have gotten 4 visa extensions in total.
– Will I have any trouble getting another extension?
– Am I going to have any trouble when entering Thailand (Ive read somewhere that after 4 extensions, the passport will be flagged and I might face questioning at immigration)
Also I should add that always enter Thailand via airport and I always bring THB20000 in cash with me. However I do not have any proof of employment since Im self-employed.
Any help is greatly appreciated 🙂