There's just been a conference in Seattle on developments toward male birth control. Here's a brief article
on the subject.
"In some cases, Lissner said, male enthusiasm for a new method may well be linked to the hope of getting more sex. Some men want alternatives because the female pill affects their partner's libido, or because she's already abandoned contraception because of side effects. Some worry women will forget or lie about contraception. Some just want to share the burden."
Given the repeated use of the word "some," this seems pretty fair. And the article mentions concern over women lying about contraception as well as men's desire to share the burden.
And here's an article
on a promising, reversible "vasectomy." It's worth noting, however, that many women had trouble with hormonal birth control when it first came out. (Some still do, but the science has been refined quite a bit.) It's always tricky when we try to mess with nature, and the chemicals involved in this new male birth control have a daunting sound, irrespective of how safe they may prove to be -- "powdered styrene maleic anlydride (SMA) and dimethyl sufoxide (DMSC)."
Caution is advised, but we have reason for optimism.