To fit into somebody's heart and somebody's life, you need to fit that person in yours. With all of his/her errors, incapacitation and apprehensions.
Relationships of any sort begin with this adjustment that is required to bring two hearts and souls close to each other. When you stand in a crowded train, you have to watch where you're standing and adjust. With so many people and so many things, you need to fit in a person.
If I like everything about that person, how is he/she different from me?! He/she is different from me because he has things that I don't like in him. And if I want him/her in my life, I MUST fit him/her the way he is.
Relationships are like sockets. You need to fit in, lock yourself and still allow the movement in the direction desired.
Relationships are not called attachments, connections for nothing.