"This will also add to my income"
Not if he did it the way you say he did it.
"and I have to file Married filing separate"
Possibly. You are still allowed to file jointly if you are still legally married, but signing a joint return means you would be taking full and equal legal responsibility for the entire tax return. You also need to be in cooperation with your estranged spouse. Filing separately may be the best legal choice even if you owe more taxes that way. The legal entanglement of filing jointly may cost you in the long run.
"He did this without my knowing?"
And also without competent financial advice, apparently.
