A cursory glance at discussions online regarding relatinoships and attraction would show that most people would say they don't decide who to be attracted to, that it simply is what it is.

Just because we can show that cheating has evolutionary benefits and thus people are likely prediposed to cheat in certain situations does not eliminate any moral considerations. Morality is precisely the idea of overriding any base instincts with what we "know" to be proper behavior. Claiming your genes made you do it is no more a loophole for morality now than "the devil made me do it" was before the discovery of DNA.