i have had the pairs together for a week now, the female is still in the glass jar but the male hasn't started building a nest yet. I've been feeding both of them brine shrimp and betta food once a day.
can anyone tell me what's wrong.

well your male might be un age for breeding. Is he 6-12 month old? If he is (and the female is in that range too and is smaller) than release the female once she is ready. Sometimes males being blowing their nest;s during breeding (althought its very rare) ( but it could be ur pair)

probably not old enough

He's still pretty young and may catch on over time, but there are Bettas who just never quite grasp this bubble nesting malarky. Do you have another male who's a bubble nesting demon? You can do a switcheroo there, get him to do the nest then move in your other male to claim it as his own! A lot of breeders keep one or two of these males around when breeding just in case!

_Hope this info helps!! =)