It appears that @MindyB overlooked the fact that you have separate self-only coverage, not family coverage. The fact that you do not have family coverage means that each of you is separately subject to the self-only contribution limit, not the contribution limit for family coverage, and must separately obtain returns of contributions from each of your HSAs.
The method described in CFR 1.408-11 is used to calculate the net income attributable to the excess contribution being returned.
https://www.law.cornell.edu/cfr/text/26/1.408-11
You'll likely have to sell shares to have the cash necessary to make the corrective distribution.
