"Just" Friends

Why is it the good ones are someone elses man? You make friends with someone who is perfect for you but yet they are taken? No Bueno!
I personally think its a huge form of manipulation that can possibly get out of had.. too seemingly sane people falling for each other but their is a huge hinderance of one being taken.
Granted marriage is not involved it’s just “girlfriend” and “boyfriend” but lines should be drawn or should they?