Your lover has been looking for a big, big love for a long time. They want someone who understands them on an instinctive, intuitive level; someone who adores them and is there for them, who is their rock and their safe haven. Somehow, though, they've ended up with some emotionally unavailable types who make them feel neglected, not well cared for.
Now, it's a good thing to learn to take care of yourself. Each of us needs to meet our own emotional needs, first and foremost; we can't just be walking chasms of need that are looking to be filled by the love of another person! That being said, each of us does need love, support, attention and affection. It's a difficult situation when we fall in love with someone who can't return the sentiment a hundred percent. This might be the case between the two of you. They could end up being more emotionally invested in the relationship than you are; they're the one who, subtly or overtly, pushes for a commitment, for a spoken declaration of love, for greater intimacy and affection; and they keep coming up disappointed, again and again. But instead of moving on to find someone who can love them the way they want to be loved, they might keep on pushing for it in this relationship, which creates a considerable amount of friction and tension.