Why is my return high when I've entered only my tax information, but once I enter my wife's taxes, I'm suddenly owing

When filing together, my tax return is $3000 before entering her tax information. As soon as I enter her tax information, I am suddenly owing $50

Troubleshooting

What might have happened is that you were getting the spousal amount, but when you added your wife's income you were no longer eligible for it and it was removed.

 

Also, there are benefits & credits that are calculated based on family income (you & your wife's), so it's possible that you no longer qualify for something because of your spouse's income.