You do have lots of options.
You mentioned putting it in your 403b to reduce your taxes, but had reservations about it being locked up until age 55. If you instead put it in your wife's 401k, it would still reduce your taxes. If she leaves employment as you foresee, she can roll the 401k into a tIRA, which you could convert to a RothIRA at some point if you wish.
Putting the money in your wife's accounts would also build up her retirement balances before she takes time off to be a SAHM. I was a SAHM for nearly 20 years, and while we view our retirement assets as all "ours", I still wish I had more in my name. I'm working now, but I don't have access to a 401k, so we max Roths for both of us, and I've convinced DH to max his 401k.
Just a few years ago, DH was just putting enough in his 401k to get the match, then they did away w/ the match and he was tempted to stop altogether, but I instead got him to tweak his withholdings to increase his 401k from 5% to 10% w/ little change in takehome pay. Little by little I had him increase it to 20%(paid off student loans), then 40% (when we paid off the mortgage), then 50% when I began working part-time, and it's now 52% to max it.
We've got kids, and our income is relatively low, so we're eligible for EITC, which phases out at a rate of 21%. NYS matches EITC at 30% of federal. So every dollar we put in the 401k increases our return by 21% + 6.3% + 4% NYS tax + 10% fed tax = 41.3%! I turn around and use that refund to fund our Roths.