You are eligible to contribute to as many HSAs as you happen to have, but note that the annual HSA contribution applies to all the HSAs in the aggregate. That is, the sum of all contributions (from your husband's employer, both of you, the mailman, anybody) to your HSAs together must be less or equal to your annual HSA contribution limit ($6,900 if your husband has Family coverage in the HDHP).
When you make the entries into TurboTax about your husband's HSA (if indeed he is the owner of both of them), answer as if you have only one HSA. The employer contribution from the W-2 will flow in automatically, and then on the screen "Let's enter [name]'s HSA contributions" (see below), enter the direct contributions that you made to the second HSA on the second line as a "personal" contribution.
So long as you do not exceed the annual HSA contribution limit, you are free to contribute to both HSAs.
