I'm not sure what you would gain by having a CPA go through your pay checks at $300 or $400/hr (or whatever they charge).

For some unknown reason, your employer under-withheld taxes. Your best recourse would be to work out a payment plan with the IRS and have your employer withhold additional money each paycheck. It sucks but a lot of us have been there.

I'm sure it has something to do with your bonus and pay raise if you didn't have the same problem last year. There are a lot of posts on this sub about the exact opposite problem, where their employer withheld taxes at too high of a rate after overt time or for a bonus. It's why so many people believe they're losing money by working OT or getting a Christmas bonus.

> What other things do you think newly-weds should consider about their finances, before and during marriage?

In terms of long term stuff... Whose career will be prioritized when it comes to moving for jobs or going back to school to increase earning potential? And what are your expectations in terms of taking care (or moving closer) to elderly parents who potentially live in another country? What are expectations for children, how many, and how soon?

The nitty gritty stuff about marriage is relatively simple for a couple that earn roughly the same income, have limited debt, and few assets. Not much will change.