The best way to learn proper English is to read news report, and watch news on TV. Watching TV shows is a great way to learn casual English, slang words, understand culture reference and humor. If you have already watched these shows then you may recall the words used in the following dialogs.

"We’ve always heard stories about husbands
catching their wives with their LOVER.
Money Heist Season 1, Episode 12

The LOVER lives the relationship
with passion, devotion, and romanticism.
Money Heist Season 3, Episode 5

I killed my LOVER with my bare hands.
Game of Thrones Season 5, Episode 1

All right, LOVER boy.
The Big Bang Theory Season 7, Episode 6

...who is not only a wonderful guy,
but also, I hear, a gentle and thorough LOVER.
The Big Bang Theory Season 1, Episode 2