Sorry, but it seems to me you have a bigger relation problem, than problem regarding your permission to stay.
However, you have 2 options like everyone have told you.
1. Go out, get single entry non-o, and extend 60 days based on wifey. (That might go tits up at any given time as they might refuse both issuing a lot of them as well as refusal to enter Thailand again) They call it abusing the visas and permissions to stay.
2. Put money in the bank, extend your non-o for a full year. Think that option might also fix some of your relationship issues. Maybe smaller trips and wifey more happy at the end. The best, you can take out the money and live on them, as long as you have more for next extension.
At last, you are making a big thing out of nothing. You are speaking like you are a hot shot investor or trader. But, I think not, as 400k baht can make you think so much about losing. 400k baht is, should be, nothing to a married man in Thailand.