wifelet

noun3

1. •
   (informal) A wife.

   • Annie, wifelet, let me tell you of one of my foreign flirtations—one that I have never yet even hinted to you. — 1857
2. •
   (informal) A wife who is of small stature.

   • In stature the Manlet was dwarfish— / No burly big Blunderbore he: / And he wearily gazed on the crawfish / His Wifelet had dressed for his tea. — 1893
3. •
   (informal) A long-term girlfriend; a mistress (the “other woman” in an extramarital relationship).

   • Now 83, he [Alexander Thynn, 7th Marquess of Bath] has a fortune of more than £150 million and famously lives on the estate with several girlfriends who he refers to as ‘wifelets’. — 2016