What is everyones thoughts on +1s at a wedding??

We are already on a tight budget and originally i had just said family only... but when planning out our tables my fiancé and my mother asked where the partners of our bridal party are and where family members partners were sitting and i said they weren't invited and they both looked shocked like you can't not invite your bestfriends partner to your wedding...in my head i say why not? Its my wedding, i dont like her partner and i don't want them there... is it terrible for me not to invite them?