Just to confirm. The MOFA regulations (which you should read) state no restrictions on activities for spousal visa holders.
*snip*
SV is not a gold card, though. It won't guarantee work. It just gives an employer an inkling that you plan to stay longer than the usual drifters here. English teachers here, except for most universities and for international schools, don't usually have degrees in teaching or education fields. You might want to look at some of the companies who want people to teach business English (Simul, Sumikin, Phoenix Associates, etc.).
For most non-teaching positions, you will have to have a fairly high level of Japanese language ability. How's yours? Unless you get hired by a foreign outfit with branches in Japan that speak only English, expect the application process to be difficult if you don't know Japanese. How else are you going to communicate with staff, read email and memos, understand the weekly business meetings, etc.?
Uh, your intended wife is Japanese, right? I ask because many people think spousal visa is for anyone who gets married, but it's really only for people married to a Japanese. The situation is totally different if you marry a non-Japanese.