I think evo psych will expand to be more descriptive as new data comes to light. I regards to the mate selection idea, I thought this was interesting:
PLoS ONE: Do Ravens Show Consolation? Responses to Distressed Others
Basically, it talks about ravens consoling one another. I think that demonstrates just how deep a role emotions play in mammalian life. If you look at the history of psychology, these emotions were discounted during the time of the behavior theorists. It's evo psych that is bringing a closer look to the survival benefits conferred by emotions such as love and empathy. I find it pretty inspiring to think that these positive feelings aren't just social constructs, but are tied directly into our biology. That doesn't mean feelings can't be misled, but they aren't as airy as might be considered at first glance.
Aaron