I suppose my answer would be very trivial. Love is a social phenomena. Society obligations, morales, laws, values WILL structure the feelings and their material representations (meetings, all levels of physical contact including sex, all levels of communication, etc). This will result in annoyance, anger, pain.
In societies where restrictions are very cruel you would expect pain. In more free societies, there is no need for such un-needed feelings. So, these extra feelings are erroneously associated with love, while they should be associated with a societal order that doesn't promote love :)