@ssam2020 -
1) you can protect your refund in case it gets to the point where your spouse is deliquent on her share. File Joint with form 8379 (Injured Spouse)
2) your issue is a marital issue (trust!) and not a financial issue. This is why the IRS created the filing status of Married - Filing Separate. If you two are not comfortable signing the same tax return, then Filing "Separate" becomes the only viable option. The IRS gives each married couple the absolute choice to file MFS or MFJ.
Congress only passes tax laws that protect the sactimony of marriage and therefore married couples are motivated to file Joint... and 96% of married couples do file Joint. For that last 4%, and you are in this camp, the tax benefits are not as advantageous as filing Joint. You may not see that as "fair", but the IRS and the Government just doesn't want to get involved in different viewpoints of a married couple, hence it avoids being a marriage counselor by creating the MFS filing status. Make Sense?
