Monogamy or Polyamory

Polyamory is such a rare word. Apparently, poly is the Greek for many and amor is Latin for love. Homosapiens are smart because we make things simpler. So another equivalent (but technically not identical) of this word was coined in 1972 by Nena O'Neill and George O'Neill in their book: Open Marriage. Unfortunately, marriage is not a concept well developed for gay people (no matter what is the reason), so another phrase comes along. Please meet out guest today, here goes: OPEN RELATIONSHIP.
Open relationship denotes a relationship (usually between two people) in which participants are free to take other partners (mainly sexual); where the couple making this agreement are married, it is an open marriage. Open relationship has been so well used inside of gay community and people may actually suspect that it is made for gay people. Monogamy is not something to mention in straight world. They follow it as instincts, moral and as stated by law. Although the law does not regulate the relationship, it regulates marriage. So is the existence of marriage justifies the existence of monogamy or just because homosexual is off the common route and marrige is barely the regulation for us so the conventional moral doesn't apply? My brain does not give me answer.
Gay practitioners of open relationship are actually smart. The relationship itself is still about two people. They love each other (at least, most of them claim so). The only thing different is they are not bounded by sex. Each of them are free to sleep with other people. Is that brilliant that suddenly, the love and the sex are totally separated?
Of course, it will be hard to argue that sex and love are inherent to each other. We don't love everyone we slept with. But is there a point that we finally find someone that we want to sleep with for the rest of our lives? How many times we have seen in a movie that right at the wedding day, the bride or groom finally find out the feeling of sleeping with the same person for the rest of their lives and freak out. Is that sad that if they just practice an open relationship, none of them will be bothered?
I think it is beautiful when they finally overcome it and realise nothing will get in their way of the commitment. I do believe that real sex means something more than fluid exchange. Under the vow of commitment, two people decided to be with each other and sacrifice their possible sexual fun out there for each other. Is this one of the point of commitment, well conventionally? Is it a concept that romance has adopted forever? I don't have anything against the polyamorist; people have the rights to choose their lifestyle. However, every time I put the term completely monogamous in my profile, I feel strange. Why are the monogamists putting down extra notes but not the open-relationship parishioners to mark polyamory in theirs? Again, that may be something beyond my understanding.
So, reader, if I have any, monogamy or polyamory, what will be your choice?