While the exact origin is unclear, here are some possible explanations:
* "Squeeze" as a term of affection: "Squeeze" has long been used as a term of endearment, often associated with a hug or close embrace. This could have evolved into referring to someone you feel particularly close to romantically.
* "Main" indicating primary importance: The word "main" suggests that this person is the most important in the speaker's life, highlighting the central role they play in their romantic life.
* "Squeeze" as a slang term for a girlfriend: Some sources suggest that "squeeze" may have originated in the 19th century as a slang term for a girlfriend. This could have then evolved into "main squeeze" to emphasize the significance of the relationship.
Overall: "Main squeeze" likely arose from a combination of these elements, merging the affectionate connotation of "squeeze" with the notion of primary importance conveyed by "main." It's a lighthearted term that conveys a sense of fondness and affection for one's significant other.