your other half
(one's) other half
One's spouse, romantic partner, or boyfriend/girlfriend. I'd love to come out to the bars with you after work, but I'd better check in with my other half to make sure we don't have any plans for this evening. The work retreat is meant to be for couples, so be sure to bring your other half!
your other halfor
your better half
COMMON If you refer to your other half or your better half, you mean your husband, wife, or partner. They invited us out to dinner after the election because they said it was time they met my other half. It's a shame my better half isn't here. You'd have someone to gossip with. Note: These expressions are usually used humorously.