First thing is about buying a house - Technically you could own the house, but you cannot own the land its on unless you are Thai
...Only other option is to buy a condo and could own it outright...provided you buy per the stipulations mentioned by one of the other posters or form a limited company and buy the house through the company...bear in mind a company in Thailand, (Non-BOI) needs to have a majority Thai stake hold ie 51?o you could only own 49?f the company...
Working wise, as mentioned you would need a job that would get you a work permit...Teaching English has been mentioned, but expat wise the salaries are pretty poor and a lot of the time English teachers/institutions they are working for dont bother applying for a W/P - This is illegal, but does go on...
As regards possible solutions - if you manage to get a job with a W/P (and extension of stay), You partner could piggyback on your Non-imm B and W/P and get a type O visa as a dependent and then look for work and then go through the W/P process himself...you would have to check on how to go about this as have heard two different versions of the rules..
Regarding building work...you partner would have to be looking for a construction manager/Supervisor job not hands on work with a big construction company...
.....Or form your own company....THB 2 million paid up capital, employ 8 thai nationals and you could get yourself 2 work permits to run the company and then could buy property through the company....this a route a lot of Farangs go to stay long term in Thailand
On the VIP visa option somebody mentioned....this is a very expensive route to go and you cannot get a work permit under this system...it used to be THB 1mil to get and recently raised to THB 1.5mil with what appears to be less benefits...understand the price has been raised due to lack of interest...!!!!!..so that should tell you something about the program...
Hpe this helps
Edit..
James B....the VIP program mentioned is the ThaiElite program put place by Khun T.S..other than fast tracking at the airport, preferential rates at golf clubs/restaurants and a 5 year renewable visa..doesnt really offer much...for the price....
THB 1.5 mil
Edit...
"Safer is to invest (over) 3 million baht in Thai financial assets that make an alien eligible for non-imm visa"
African Famer...Stand to be corrected but you can not obtain a visa this way any more....People getting visa's this way in the past will be honoured but no new visa's will be issued
Edit..
Khun African Farmer
Thanks for the link....but see this link
http://www.sunbeltlegaladvisors.com/Thailand-Investment-Visa.php The link you have given is related to being approved under the BOI system...which think would be hard to get under the OP's circumstances...plse correct me if reading something wrong here
Baie dankie...lekker dag..