Typically, there is no male equivalent to the female’s engagement ring. Many couples are okay with this. Others choose not to have an engagement ring at all, and just wait until they have the wedding rings. In others, the woman gets an engagement ring from the man, and the man gets an engagement gift of some value from the woman. (For a somewhat silly example, I knew a couple who became engaged a few years ago, and he got her a ring, while she got him a car stereo… ;) )
As far as the “three months salary” thing… that was frankly made up by jewelers… ;) Three months’ salary is a lot of money for most people, and—while I understand it’s a sign of commitment—it hardly seems responsible to enter into your new marriage having just gotten rid of such a (relatively) large portion of your assets. (Or worse, gone into debt for it.)
I think for most couples, one month’s salary is probably more reasonable…