What was it that first drew you to them? Similarities? Differences? Were there other, smaller relationships? If so, how did they bear out?
As someone upthread asked, what was your father (or relevant stand-in) like? How did your mother (or relevant stand-in) relate to him? Were there - are there - particular relationships, real or fictional, that you idolised?
You describe them as intellectual, rather than intelligent. With that in mind, and that you didn't feel they loved you, what occurs to me is the idea of them as aloof, distant, emotionally cold even. Some people like a challenge in romance - in this case, do you perhaps want to 'thaw' them, to be the one who starts an uncharacteristic passion in them?
What could/should they have done to make you feel loved?
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Of course, it's probably quite a bit more complicated than that.
You know sometimes, between the dames and the horses, I don't even know why I put my hat on.