you pick who YOU want in the bridal party. the constituents having s.o.'s has no bearing on who you should pick.
as an example here was our bridal party:
matron of honor: bride's sis(sis' husband not in bridal party)
best man: my best friend(his wife not in bridal party)
bridesmaid: bride's best friend(her husband not in bridal party)
bridesmaid: my sis(her bf not in bridal party)
groomsman: my bro(his gf not in bridal party)
groomsman: another buddy(his gf not in bridal party)
this is YOUR wedding, and hopefully you only have one, so YOU pick only who YOU want.
and good luck!
