I've just watched to movie Bobby in the following dialog takes place

The reason you're
getting married.
Love or money?
I'm saving a life,
marrying a boy from my school.
There's a lot of that
going on these days.
The government sends a check
to the spouse for $135 a month.
I assume by "saving a life" she means that he will avoid the draft, but I though married men were "called up" and whats the $135 for?