This is IRS recommendation ! As Tax Preparer, Strictly have to follow IRS guidelines.

IN GENERAL, WHEN A U.S. CITIZEN OR RESIDENT ALIEN IS MARRIED TO A NONRESIDENT ALIEN, THEIR FEDERAL TAX FILING STATUS IS MARRIED FILING SEPARATELY.

HOWEVER, YOU MAY CHOOSE ANOTHER FILING STATUS IF YOU QUALIFY.

IF YOU CHOOSE THE MARRIED FILING JOINTLY STATUS, BOTH SPOUSES MUST REPORT THEIR COMBINED WORLDWIDE INCOME.
BUT, IN GENERAL, REMEMBER…IF YOU DO NOT CHOOSE TO TREAT THE NONRESIDENT ALIEN SPOUSE AS A U.S. RESIDENT FOR TAX PURPOSES, AND YOU DO NOT QUALIFY FOR HEAD OF HOUSEHOLD FILING STATUS, THEN YOUR FILING STATUS WILL BE MARRIED FILING SEPARATELY.

THIS SUMMARIZES SOME OF THE OPTIONS AVAILABLE FOR TAXPAYERS WHO ARE MARRIED TO A NONRESIDENT ALIEN.

FOR INFORMATION ON ALL TYPES OF INTERNATIONAL TAXPAYERS, PLEASE VISIT IRS.GOV AND TYPE “INTERNATIONAL TAXPAYERS” IN THE SEARCH FIELD.

Source:https://www.irs.gov/newsroom/international-taxpayers-filing-status-if-married-to-a-nonresident-alien-youtube-video-text-skript

Regards,
A Square Accounting
https://asquareaccounting.com/
Email: asquare.acctservices@gmail.com
Phone: 406 345 5166