Make sure you consider that your wife's feelings may change. You don't want to keep working until she feels uncomfortable supporting you because then you put the burden on her to raise the uncomfortable question of "can you stop?" (Especially since she doesn't want to doubt you, damage your self confidence, or hold you back from your dreams.)

She's your publisher and you need to set and meet milestones. If you don't hit them, it's your responsibility to prove why you should keep working at it. I think you want to do what you can to set yourself up to see the writing on the wall instead of relying on her to ask you to go back to a paying job. If it takes you five years to make your first $1k, then how will you measure your success and whether you should quit? Escalation of commitment is a mental challenge to overcome.

Also, what funding can you get? (Gov't art/media grants, SR&ED, etc). Can you work a part time job a few days a week? (Maybe you can work out dedicated development days instead of trying to dev by night.)

When I tried solo, I found I needed more human contact. Can you spend 3 days alone in a room? Will you find a shared workspace? Will you find collaborators (/r/gameDevClassifieds)?

(I stressed my wife, used up my nut, gave up, and now work for a studio. I wish I had set better, SMARTer, smaller goals, and stuck to them.)

I want to make games for Steam as this is what I use the most.

You're going to need to learn marketing. Look up other old posts on this subreddit for greenlight.

In the meantime, create an itch.io page which will allow people to purchase your game and you don't need to get approval. itch.io is intended to help you build a showcase for your games, so put your old ones up there so people can see you have some history.

You could read this post about Minimum Sustainable Success.

I've been making games professionally for 8 years and I still underestimate how much work it is to just make the game let alone market/distribute it.