It wasn't just a manner of salary and general living expenses. An officer also had to buy his own uniform and other equipment. Plus, he'd have the expenses of a horse(s), servant(s), mess bills, and otherwise conspicuously "living the life of a gentleman" (unlike giving the image of a frugal clergyman).

However, senior officers were expected to turn to matrimony. One contemporary (read it recently, but can't recall where) remarked (to paraphrase):

"Subalterns should not marry; Captains may marry; Majors should marry; Colonels must marry>"

The gist being that for a young officer a wife and family could interfere with his military activities and duties (and vica versa). As he got older and assumed greater responsiblities, a family could be a useful steadying influence. (Plus, giving a certain image to the rest of the army.)

I remain,
Jason E.