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We're not sure if this situation means we should file separately or not. We don't know what effect her having a business has on our filing status, or whether her daughter is legally my dependent just because we're married.
It is almost always more advantageous to file Married Filing Jointly since there are credits that are no longer eligible when you file Married Filing Separately.
The child would be claimed by the person that supplies more than half her support.
The business income should not have any less effect collectively if filed together with your income or separately.
You can use TurboTax Online to compute returns both ways and see which way is better for you.
HERE is a link with more help
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