According to a team of scientists led by Dr. Helen Fisher at Rutgers, romantic love can be broken down into three categories: lust, attraction, and attachment. Each category is characterized by its own set of hormones.
Sexual desire is driven by Testosterone and Estrogen. This is purely about the desire for sex and reproduction.
Attraction by itself is not sexual, so this includes “liking” people - parents, friends, brothers and sisters. You will probably notice that you are more “attracted to” people that you feel comfortable around, such as people who are confident, or people who are of the same ethnicity as you.
“Pair bonding” is driven by Oxytocin and Vasopressin. This keeps people together, and is responsible for the “I miss this person” feeling when you’re apart. Parents and children have this, or mom would have abandoned you long ago (you screaming little miscreant). Romantic couples have this as well. Among other things, these hormones are elevated by regular sex, which is why when “the sex stops” in a romantic relationship, it’s unlikely to last. It’s also why long distance relationships are so difficult. No sex = no oxytocin = you lose that special feeling we call “love”.
All of these hormones can exist in different measure, at the same time.
That’s why you can feel Lust & Attraction, but no Attachment = “the lover”
Or, you can feel Attraction & Attachment, but no Lust = “friends & family”
The BROJO inner circle session on Love & Hormones had a good look at these.