Married in 2023, want to file separately

Hi, I got married in 2023, and my spouse has a sizeable tax bill that he still owes from past years so we want to file separately.  I make approx $100K/year on a W2 and he makes about $30K/year on a 1099 (gig work).  I have one college student from my previous marriage (age 19) who I support 100% and still claim as a dependent.  My question is: how should I complete my W4 so that I don't end up with a tax bill next April?  I would strongly prefer to get a tax REFUND.  Thank you!