Unless your significant other is an orphan with no kids, you are going to have baggage.  There will be ex-spouses, children, spouses of children, children of children, parents, siblings, aunts, uncles, and cousins.

This is known as a family.  And, like it or not, it is a package deal.  They come with your significant other.  So, you need to be prepared for what ever lies ahead, like it or not.