History/usage: 耦 vs. 偶? According to the ABC dictionary 耦 means:


  a couple


as a noun and


  to couple


as a verb.

Think of words like:


  去耦


meaning decouple.

But, 配偶 can also be written: 配耦.

What is the history and usage of 耦 vs. 偶?
In terms of historical usage, the word meaning likeness, couple (Zhengzhang: /*ŋoːʔ/) was first written as「禺」as a phonetic loan, then


Had「亻」added to it to differentiate this meaning from the other meanings written「禺」;
Had「耒」added to it to specifically indicate the meaning two people plowing fields.


My speculations: Since the word represented by「耦」is related to「偶」(in fact, identical, just written with a different glyph for a specialised circumstance), they became interchangeable to a very large degree.「耦」was even used for the word idol:


木耦
土耦
耦人


The current spelling would then be just dictated by educational committees, as historically they were the same word written with two different glyphs and frequently mixed up in usage.