There are feelings of 'quiet desperation' you your partner puts on you for having any needs.
When you ask for closeness or intimacy, you're labeled as being "too needy." When you try to have an adult conversation with your partner about your concerns, they might is one too!
The core relationship, most likely the relationship with the mother, was damaged early in childhood, and their basic needs were not met.
Carrying this damage into adulthood, something will emotionally trigger them back to these memories, and they will respond to their partner in the same way as they had to their mother (core relationship).
This stems from child abuse or abandonment they suffered at an early stage of development, which led to them having Borderline Personality Disorder in the first place.
For someone with Borderline Personality Disorder, the past and the present are, many times, melded together.
One of the major characteristics of Borderline Personality Disorder is that those with the disorder will push away the very people they love (need) the most.
This doesn't mean you won't get a crumb or two along the way (if she --and you'll pass it off as such.
As the years go by, you're faced with the dreadful awareness that this 'phase' has become permanent--but it's impossible to leave, without severe financial repercussions.
By now, you're in too deep to extract yourself--and besides, you're not the kind of guy who breaks his word (no matter what)!
You start thinking that if you try a little harder to please her, that girl you were crazy about will return--but it seldom happens.