[kappaloris]

Do you care at all about what your company does? What did you hate about your startup experience?

While I'm not in your position, I fear that I will one day end up in a situation where I'm working on something that I don't care at all about and regardless of what the job gives back in terms of money/prestige/experience, I won't be able to 'unsee' the fact that I'll be wasting my life for the benefit of a third party.

As of now the only thing that really keeps me motivated is a combination of a challenging problem (not being 100% sure to be able to solve it elegantly) and working on something that I care about personally. Unfortunately it seems to me that this kind of combination is most likely found in the startup world, which means you also have to deal with its generally awful culture.

Maybe you too can find a way to keep motivated, although having a family surely reduces your possibilities. A side project maybe?

If you can't change your working situation then you must find a way to 'recharge your batteries' outside of work and since you have a kid on the way you might also want to consider something that you can share with him/her in the future.