@peterpumpkineater wrote:
living apart for over 2 years and have a dependent.
This is a complicated area and I don't think any of us are experts. You should start by reading IRS publication 555.
https://www.irs.gov/publications/p555#en_US_202001_publink1000168814
The situation is governed by state law. If you have community property or community income even though you are separated, you must still divide it according to state law.
A marriage can have both community income and separate income. For example, investments you own before you get married might be separate income and only reported on your MFS return, while income from your job during the marriage is part of the marital community and is divided equally even if one spouse doesn't work.
The question you need to ask of your state laws is "when does the marital community end?" If the marital community ends on separation, then your income is no longer community income. For example, if you separated on July 1, 2019, then you might have community income before that date and separate income after that date. Then for 2020, all your income would be separate income.
But if your state has different rules on when the marital community ends, or if some of your joint property is still considered community property even when you are separated, then you have to follow those state laws. Again for example, suppose you and your spouse own a rental building together. Even though you are separated and your job is now considered "Separate income", the income from the rental may still be "community income". It all depends on your state laws.
You may need the help of a tax preparer in your state.
