I currently identify as Asexual with humans, but when I was in my teens, twenties and early thirties, I identified as straight in my younger years and dated quite often. I saw in those years that my desires for women began to fade as I got older, in those same years I preferred to be with female canines. Although I did have sex with male canines, there was far more emotional stimulation with female canines for me. It wasn't until I "adopted" my first male dog that I was able to have a chance to build an emotional relationship with a male, now I love taking a knot just as much as I love breeding a female.
I will say that sex with both is very different for me, when I am breeding a female it is purely "love-making" for me. The kissing, the body contact and the idea of filling my female lovers womb is so Spiritual and Natural. But taking a knot, having my stud dig his claws into my waist, feeling his hot breathing on my neck, his fur on my backside and his cum filling my guts is so Goddamn wild.
My past female lovers were definitely like my wives and my current male lover is definitely like my husband. I treated my canine wives like queens and pampered them in ways that should've made it obvious to everyone around me that our relationship was more than what they knew it to be. Now, I treat my canine husband as the dominant, he dictates when we go on walks, I only eat when he is hungry and when he wants his sexual needs met I make sure that they are served when he demands it. I don't go anywhere without him and if he can't go where my family/friends want to go, then I don't go either. (But I live in a country town and it isn't really weird that my lover and I are inseparable.)
Just for further reference, I still love seeing women in human porn and it still turns me on. But I just don't desire romantic connections with women.