With regrets, am going thru a marriage separation, & trying to make an informed decision, if best to file as married, joint? or, as married but separately (MFS)? -bch-

[xmasbaby0]

If you were legally married at the end of 2022 your filing choices are married filing jointly or married filing separately.

If you want to file a joint return BOTH of you must agree.   And...if you are the custodial parent of the children and have been separated for at least the last six months of 2020, you may also be able to file Head of Houseold.

Married Filing Jointly is usually better, even if one spouse had little or no income. When you file a joint return, you and your spouse will get the married filing jointly standard deduction of $25,900 (+$1400 for each spouse 65 or older)  You are eligible for more credits including education credits, earned income credit, child and dependent care credit, and a larger income limit to receive the child tax credit. 

If you choose to file married filing separately, both spouses have to file the same way—either you both itemize or you both use standard deduction. Your tax rate will be higher than on a joint return. Some of the special rules for filing separately include: you cannot get earned income credit, education credits, adoption credits, or deductions for student loan interest. A higher percent of your Social Security benefits may be taxable. Your limit for SALT (state and local taxes and sales tax) will be only $5000 per spouse. In many cases you will not be able to take the child and dependent care credit. The amount you can contribute to a retirement account will be affected. If you live in a community property state, you will be required to provide additional information regarding your spouse’s income. ( Community property states:  AZ, CA, ID, LA, NV, NM, TX, WA, WI)

 If  you are using online TurboTax to prepare your returns, you will need to prepare two separate returns and pay twice.

https://ttlc.intuit.com/questions/1894449-married-filing-jointly-vs-married-filing-separately

https://ttlc.intuit.com/questions/1901162-married-filing-separately-in-community-property-states

https://ttlc.intuit.com/questions/1894449-is-it-better-for-a-married-couple-to-file-jointly-or-separ...

[Opus 17]

There is no single correct answer.  You are always allowed to file jointly if you are legally married and you agree to file jointly.  Joint filing usually results in lower tax or a larger refund, because some deductions and credits are limited or disallowed when filing separately, but the only way to know for sure is to test both ways.

On top of that, you have to agree how to split any tax owed or refund (you can request that a refund be split into two bank accounts, but if there is a banking problem, the IRS could put all the refund into one account).  Also, when you file jointly, both spouses take joint and several liability for all the income and claims in the tax return. That means that if there is a deficiency or error, the IRS can come after one spouse, the other, or both, as they choose.  (In other words, suppose your spouse is working under the table and you sign a joint return, the IRS can come after you alone for the tax deficiency if you are the easier target.). If you file separately, you are only taking responsibility for the facts and claims you sign your name to.