I find it ironic that the people who immediately jump to the topic of sex when the word "homosexuality" comes up are precisely the same people who condemn the evils of sex (at least, extra-marital sex) and how we shouldn't think about it. I believe it is people like that who do not understand love.
Sex is a wonderful, beautiful part of love. Two people who are in love should engage in whatever sexual activities the two of them feel comfortable with. But, to think of a relationship as just sex is so shallow and superficial. Love is so much more than that.
But, we also want a special someone (or someones, in the case of polyamorous people) with whom to be more intimate than just friends. We need a deeper connection--someone with whom we can share everything. Someone who will laugh with us and cry with us. Someone who will feel and understand our emotions. We want someone to rely on, to trust, and to be loyal to.
What does it mean to you to love someone? To me, it means that you wake up in the middle of the night to carry your wife to the bathroom when she has pericarditis. It means that you make a peanut butter and jelly sandwich for your husband when he's running late and doesn't have time to eat breakfast before going to work. It means that you're available when he needs someone who will listen to what's going on in his life. It means that you'll understand him when he tries to express himself to you.
To face the world with a companion at your side is no challenge. By yourself, a task may seem formidable, but with your best friend at your side, you can accomplish anything. This is love. You do not view your lover as an adversary. You view the dangers and difficulties of life as the adversary, and your lover is there as your ally to help you through all of those times. To love him is not to fight against him, but to fight with him against any obstacle in his way.
And, yes, you do have sex. And sex is a wonderful, beautiful, and amazing part of a relationship. It draws the two of you closer together in ways that only sex can. It is not something to be ashamed of. It is not something to shy away from or to avoid discussion about. It is something to rejoice in, something to embrace and experience. To share with your partner all of the happy endorphins that sex causes to be released into your brain is sublime. It is the icing on the cake. It is a natural consequence of being in love. And it makes sweeter any romantic relationship where it is shared. But, it is not the only aspect of love--whether that's gay love or straight love. It is not an end in itself, but it is a means, with love as its end.