If you love them and spend time with them don't re-home them :) They both still have a lot of life left in them and many years down the road if one passes before the other you have options. You can either adopt another glider to make friends with the one you have left or you can then re-home the one left to be introduced into a new colony. There is always the option that the one left might be alright on it's own for the few years it will have remaining as well you will have to wait and see