Could one use the word "wifey" instead of "wife"? I found many conflicting definitions online, Macmillan dictionary says it can be referred to as on'e wife in a humorous way or insulting way. Another meaning- It's referred to an old woman. I am not sure if the native US or UK speakers recognize this word and use it.
It's a recognised word, but its use is either old fashioned, or humorous, or occasionally affectionate.
In normal, modern, usage, on most locations, no one would use the term as a common synonym for 'wife'.
There are some areas where it would be considered nothing more than an informal, affectionate, term for the speaker's wife.
Although 'wifey' can be used affectionately, many people in English-speaking countries see the word as misogynist, sexist, and infantilising. There may be slight nuances of meaning, e.g. in American English, a single woman may be considered 'wifey' if she is stereotypically suitable marriage material for a sexist type of man, and in the UK, it may be a word used casually by husbands to refer to their wives.
Either way, it is insulting.
...why does this insult still hang around? And why does it infuriate so acutely?
For me, it’s the reduction of my complex identity to a label that has the condescending, infantilizing singsong tenor with which you might speak to a child. Wifey. Baby. Honey. Sweetie.
NOUN COUNTABLE BRITISH INFORMAL
1 an insulting or humorous word used for referring to someone’s wife
1a a woman, especially an old woman. This word is sometimes considered to be insulting.