Its a fun activity to be enjoyed by two people.
Or three. Or more. Or, arguably, by one.
I'm interested in why you feel that evolutionary psychology has such a low credibility. I'm not deeply well-read on the subject, but I wouldn't have said that it was significantly less-credible than psychology as a whole (which, of course, produces testable theories, although it's often incredibly difficult to isolate biases). As far as I understand it, evolutionary psychology is simply about the study of the possible evolutionary reasons for psychological phenomena.