I'm able to find research and commentary on the potentially disruptive affects switching on (or off) the pill during a relationship that began when off (or on) it can have, but not an attempt to systematically look at the influence increasing pill penetration into the US market has had on sexual behavior. Here are a couple of graphs from a CDC report that give some sense of how pill usage has increased over time--a trend that is unlikely to reverse with health insurance providers being mandated to include coverage for contraception:
This is speculative, of course, and the increases in the share of sexually active women using the pill at any given time has only increased from the low teens to the upper teens over the last thirty years (though NAMs are less likely to use the pill (p8) and the NAM percentage of the population has increased markedly in the last three decades) so any associated affects on mate choice probably only matter at the margins. Still, the thought that something putatively liberating like the pill could actually be gently shifting female preferences in the direction of mundane providers and away from bad boys is kind of funny.
* Based on self-reported behavioral surveys and sexually-transmitted disease rates. It is possible that women low-ball their partner counts more now than in the past. That doesn't seem particularly likely, however, since slut-shaming was presumably worse in the past than it is today, and consequently the expectation would be for women to be more honest than ever before because "omg don't judge!"