Reader wonders: Is parental jealousy normal in life?

Dear Amy: Do you think it is normal for a parent to be jealous of their partner's love for their (shared) child?

When my dad was alive, my mother would constantly get jealous of my relationship with him.

I grew up a tomboy, and my father and I were very close. My mother would make comments that disgusted me, insinuating that our relationship was somehow in competition with their marriage.

Recently, I became aware that this isn't as unusual as I'd previously believed it to be.

I hear and see comments from parents, jokingly or otherwise, stating they are jealous of the attention/affection their child gets from their partner.

If things are truly unbalanced, I suppose I can understand it.

But generally, I would think that a parent would love seeing their kid be adored by their partner. Am I missing something? I am childless and intend to remain so, therefore I do not offer my opinions to people who feel this way — except for my mother, who would sometimes apologize after making her comments.

But inside, I can't help but feel that jealousy, of all emotions, is immature for anyone, let alone in this dynamic.

Can you offer some insight?

Dear Confused: I have news for you: adults can be immature, and while many parents rise to the maturing process and challenge of having children -- for others, the strain of folding another relationship into the family system causes them to act out.

If you think of a marriage relationship as a straight line between two points, adding a third point creates a triangle, and in the geometry of human relationships, the triangle is the toughest shape to navigate.

So yes, I believe that jealousy between partners is quite common.

I've seen marital jealousy expressed regarding babies, children, house pets, close friendships, and a person's career or hobbies.

It can be tough to witness a child's preference toward the other parent. But yes, mature and balanced people learn to not only tolerate, but celebrate this closeness.