But it is that relevant to the question? You aren't asking whether people would enter into a relationship with someone they aren't sexually attracted to.
Sexuality plays a pretty big role in deciding who you are attracted to and subsequently fall in love with. It's no coincidence, for example, that I've only ever been in love with women. And I've never been in love with a woman that I wasn't sexually attracted to. It's not uncommon, in my experience at least, for woman to gradually become sexually attractive as you get to know them, even if you didn't find them sexually attractive at first glance, but for me this attraction is essential to falling in love with somebody.
In other words, in the hypothetical example given in your original post, I would absolutely imagine that I'm sexually attracted to my partner.
What is the point of being sexually attracted to your partner if you're never going to have eex with them?