when parents don't love each other
when parents don't love each other, they don't love each others family. when they don't love each other's family, they don't love the family of their child. the child feels alone and can't show too much love or devotion to either side.
when the parents remarry and have children, they love that new spouse, and that new spouses family. the first child has to watch while the parent loves and gives preference to that new child's whole family.
this state can continue for the first child's entire life. watching the parents ignore 1/2 of the first child's family, and giving preference and love to the latter child's entire family.
i have lived this as the first child. the anger at the callousness and unfairness never really subsides. And then they wonder why you're angry and why you never really seem to "get over it."
when the parents don't love each other, they should just give the child up for adoption rather than making the child live like that.