do not buy any female bettas, and do not attempt to breed bettas. it is a very time consuming, space consuming, sanity consuming venture. i've tried, i know.
as well, with 'pet store bettas', the gene pool you are breeding from is unknown and could be very poor. with so many of these 'mutt' bettas in stores already, you do not want to be bringing more into the world.
male bettas build bubble nests because that is what they do, because they are happy, and because they can. this does not mean they need to mate. they won't hurt themselves by building a nest and not using it for breeding. all my male bettas have built grand nests and nothing bad ever happened to them when those bubbles didn't get used for baby bettas.
ps - your threads are not getting deleted, you just haven't subscribed to them, so they are not showing up in your subscribed posts. here are all your threads:
http://www.aquariacentral.com/forums/search.php?searchid=1839584