Not to confuse sexuality with "love;" but is there evidence of monogamous "loving" homosexual relationships in the animal kingdom?
I was raised on a cattle ranch in Wyoming. I've seen cows hump each other...as I've seen dogs hump each other. Humping is pretty common in the animal kingdom. But monogamous relationships are pretty rare. I'm no expert on animal husbandry, but I've observed that animals do what they do for reasons other than "love" relationships. Often times, humping is a "signal" to bulls (for instance) that the heifers are ready.
It would seem that the comparison of "homosexual behavior" in the animal kingdom with humans is tenuous at best.
Otis