I dont know if I filed married filing separate or married filing jointly this year? I have student loans and I read where both incomes can make loan amt increase?

Can someone give advice on what to do? My husband and I were legally separated last year so I filed my taxes as separate last year. We are back together and are planning to do married filing jointly ( so that's what I used on my W4 for the first half of the year ). Then I can't remember where I read it , but it says if you have student loans ( which I do), now they will be using the combined income to calculate the payments which will be higher. I have always paid my own student loans without my husband's income since those loans are mine and I have never made him responsible for them . If I change back to married filing separate, more taxes will be taken out of each paycheck ~300 per pay period ..or will the difference even out if I just pay the higher student loan payment with the joint income? Its so hard to find answers online and I am so lost. Hopefully my question makes sense.