I'm a mr. nice guy. It's really crap. I'm not interested in a woman unless I can form a good friendship with her first. Then, by the time we're friends she knows me well enough not to fancy me! I can't stand the ambiguity of friendships with females. Once they know me they think I'm a nutter and maybe I am, I've lived through some ****ed up times and thought so long and hard about many things it makes them difficult. For instance, if you tell somebody you love them isn't that kind of like emotional blackmail? It's like saying "If you don't love me I'm going to suffer". If you tell somebody you love them then it also becomes their duty to look after themselves, cutting down short term solutions like drugs and alcohol or suicide. But then whose right is it to deprive the alcoholic or the suicidally inclined of a guiltless path towards self- anhilation? If you really loved such a person wouldn't you leave them to it and respect their wishes beyond a self-interested desire to keep the emptiness of grief out of your life?

On the other hand love is such an ambiguous word; you love your friends right? I do. So love can be returned on a non-physical basis, this makes it easier for a person who is not physically attracted to return love. So, to say "I love you" isn't necessarily a big guilt trap, it's easy to return love as a friend. On the other hand there's nothing like physical contact to express affection. Physical contact of any kind could spark sexual jealousy, once this "friend" takes another, a lover, you're left aside so your GTI doppleganger can enjoy a more complete "Friendship" with your friend without becoming jealous.
Perhaps the most important practical difference between friendly and erotic love is jealousy. Erotic love has an element of jealousy, we're happy to share our friends but not our partners. There's a genetic reason for this, genes which code for jealousy and "protection" of a propogator of fit genes outcompete sharing genes that respect the freedom of another more completely.
Perhaps mass swinging could reduce jealousy, if everyone shared perhaps nobody would be so fussy and mingers wouldn't be so deprived of happiness. Things would end up like some big commune, perhaps it would allow a greater de-coupling between the concepts of friendship and of erotic sensation bt perhaps then resultant children would have no particular paternal parent to call their own. Tons of unwanted babies would turn up, loads of STDs.
So, you can't win. Nobody does. Then we all die.