Sometimes, it works out great and sometimes not so good to be dating or married to band members.
A couple that worked out well.
Pat Benatar & Neil Geraldo
Rindy & Marv Ross of Quarterflash
Some that did not work out so well.
Fleetwood Mac
Heart
Can't forget No Doubt. Chick lead singer got dumped by the bass player...and that inspired her to write enough hit singles to make a multiplatinum album for the band. And both of them stayed in the band.
So sometimes even bad breakups can be a good thing in the long run. But YMMV.