It is completely OK for you to not update your W4 form with your employer due to your spouse’s change in employment status. When you filled out your W4, it asked you how many withholdings you are claiming based upon how many dependents you have and unless you got divorced, had or adopted a child, had a child leave the nest, or had a relative move in or out of your home, then your answer to that question has not changed.I’m going to presume that on your W4 you entered 2 - for yourself and your spouse. Based on that number, your employer recalculates how much of your paycheck they withhold to pay your federal taxes. The higher the W4 number entered (meaning the more people that paycheck supports), the less your employer will withhold and the more you’ll be able to bring home every payday.The logic behind this is so that large families will have enough money on-hand to cover life expenses and because tax deductions for dependents at the end of the year usually mean less taxes are paid overall by larger families. The idea is to have the right amount of money taken out of your paychecks so that you don’t owe the feds any money at the end of the year but that they don’t owe you any money (a return) either.Some people really like overpaying their taxes though because they enjoy getting them returned at the end of the year. A common tax strategy is to claim (or enter) 0 on one’s W4 so that their employer will withhold the highest amount of taxes allowed by law, leaving them with the smallest possible paychecks, regardless of their family size (and obviously, because claiming oneself would be 1).If your spouse’s internship was a paid one, s/he had to fill out their own W4 and provide the same information. If it was an unpaid internship then the IRS doesn’t even care about it at all. They only care about the money (and benefits) actually made by individuals.In conclusion, the advice of a tax professional is always wise to obtain if you have any questions about your liability and the process of filing accurately. Licensed tax preparers are qualified to answer simple tax questions and are much much much cheaper than CPAs are but, I’d recommend a CPA if your taxes are complicated or you make over 100k annually.Good luck. And don’t forget, you only NEED to change your W4 when you add or subtract someone from your household, but you CAN change it at any time to any number you want (0–10+). Peace and happy tax season!