I don't think we are our worst thoughts. Sure guys think about sex every 3 minutes but we're not a bunch of women clubbing apes. We respect the people we're with and we care about their interests. We treat them as such.
I think honesty in relationships is hugely key, but only constructive honesty. Telling someone only what they want to hear is doing them a disservice. But scratching every itch that comes into your head is equally unhelpful. Criticism is something that needs to be thought out and analyzed before handed out (or received). In my experience initial critical instincts often tend to be based on societal norms, prejudice or other forms of unoriginal thought.
I dunno, you can see plenty of women clubbing apes in Sheffield on a Friday night...