your better/other half
(one's) better half
One's significant other (typically one's spouse). Oh, there's my better half! Honey, come say hi to some of my work friends! A: "Wait, Jennie is Ken's better half?" B: "Oh yeah, they've been married for years."
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.