This would be my second time. The first startup got started right after my wife gave birth to our second child. And not gonna lie, the challenges introduced by that very nearly wrecked our marriage. But the alternative of a BigCo job would have killed me on the inside, and I'm very lucky to have had my wife's support then and now.

If OP's wife is pregnant I would not recommend switching careers right now. That would be maximizing time away from home when you are needed most. But that's not how I read the OP:

> if I need a full time position once my wife and I start having kids

Sounds like they're still thinking about it, and maybe a few years off.