there is no limit on the number of health insurance policies you can have. the issue is that the "full coverage" policies must all meet the high-deductible test to maximize the ability to be covered by HSA(s). (certain types of policies do not count for the HDHP test such as dental, cancer, vision, accident, disability and other limited coverage insurance) these is no such thing as a joint HSA. with separate HSAs you could pay her qualifying medical expenses and she could use her's to pay your medical expenses. with both having an HSA the maximum contribution can be split between the accounts any way you want.
an HSA can't be used to pay for health insurance.
you didn't say what type of health insurance coverage you have because if either spouse has family coverage, both spouses are treated as having family coverage or it's possible that both spouses have family coverage under separate plans. with family coverage, you must use the policy with the lowest annual deductible to see if the high-deductible test is met.
