Yes, if you are filing Married Filing Separately on your Federal return, you do have an option within TurboTax to file your Maine return as Married Filing Separately as well.
Under the Personal Information Tab, under You & Your Family, tell the software that you live in Maine. It will ask you about your husband's state of residence, as well, and you can type Texas in the box.
Once you've completed that information, continue through the questions. When it asks, "do you want to file this return together with your spouse," choose No. Make sure you indicate that you are Married.
The software will then choose Married Filing Separately as a filing status for you.
Continue the Federal tax return, and then the software should transfer it to the State of Maine.