your better/other half

(one's) better half

One's spouse or romantic partner. I'd love to come out with you guys after work, but I'd better check in with my better 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 better half!
See also: better, half
Farlex Dictionary of Idioms.

your other half

or

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.
See also: half, other
Collins COBUILD Idioms Dictionary, 3rd ed.

your better half

your husband or wife. humorous
See also: better, half
Farlex Partner Idioms Dictionary

your better/other ˈhalf

(informal, humorous) your wife or husband: I’ll have to ask my better half about that.
See also: better, half, other
Farlex Partner Idioms Dictionary
See also:
  • (one's) better half
  • halves
  • one’s better half
  • one's better half
  • better half
  • so much the better
  • all to the better
  • all the better
  • better half, my
  • (one) (had) better be off