We want to work as a couple.
A family-run organization would be your best "corporate bet." But a side-hustle, growing your business together, is also a potential idea. Based on skills/experience/strength of network, is your day job something you could eventually do independently? Do you and your significant other's skills complement each other? Most businesses can be organized by operations, marketing, and finance - do you have those skills covered between the two of you? The other (harder) avenue is to identify a product or service that you're familiar with, that you wish was better or somehow different, determine the solution, then develop a business plan around that. It's lots of work but can also be incredibly rewarding (listen to the "How I Built This" podcast for heaps of inspiration). There are also plenty of "wannapreneur" blogs and resources out there, as the side hustle has definitely become a phenom.
Explore your options, have a long (realistic) conversation, and then go for it.