Premature ej-culation

So,

I was thinking about all the Australian ads on TV, radio, signs on big boards next to the road etc about guys and their "big problem" about premature ej-culation.

First of all; whatever. I guess you could say it's easy for me to say, because I'm a woman and that whole thing is pretty distant to me. But it's such a Developed country problem.

Secondly; I was getting a more biological perspective on it. Guys that this "phenomenon" is happening to; should they be more biologically efficient? If we look at other animals, maybe it's better that the male quickly spreads its seed so that he can impregnate yet another female as soon as possible? Does this apply even to humans?

I _am_ aware of the different sociological perspective that needs to be taken into account. I mean, contraceptives have pretty much minimised the "risk" of pregnancy (G-d, that is really retarded, if you look at it biologically), so it's more the "female's choice" when this is going to happen. And what does the woman want nowadays? APPARENTLY "longer lasting s-x" as all the freakin' retarded signs say everywhere. I have no opinion in that matter, but I do want to raise an issue;

Let's hypothesize that females turn down men as potential continuing lovers (and thereby also as mates that will give offspring) if they are not pleasing them in the bedroom, ergo, if they don't give them "longer lasting s-x"? And by doing that; are we messing with "evolution" and giving guys that don't impregnate females "as quickly" more chance of giving offspring than the ones that have premature ej-culation? Because, as most women that I have come across, may always use contraceptives, but apparently we all want children one day, and simply stop using the contraceptives and get a child with that person that has been giving them that "longer lasting s-x".

This is really retarded, but I just thought I should write something down about it. I find it interesting, weirdly enough. :S
Are we messing with evolution? _Can_ we mess with evolution?