I just don't understand the grow up part. Grow up to what?
Grow up to being a responsible MAN.
Does wanting a fulfilling sex life make me childlike?
NO. It's not what you want that makes you childlike. It's the WAY you want and your attitude with wanting that comes across as childlike IMO. You and everyone else are allowed to "want what you want." However what you are not "allowed" to do when you don't get what you want is to name call, get resentful, blame others, pity yourself, manipulate, throw tantrums, throw things, hit your brother Oops I was giving you the same speech Raven and I give his daughter when she doesn't get what she wants. That's what I mean by childlike reaction to not getting what you want.
It almost sounds like your saying that grown men don't need sex very often.
No she was not saying that at all.
If I need to grow up, what would indicate that I have grown up?
When you recognize that your wife actually needs empathy from you and needs a protector. When you decide to become responsible for how you react to not getting what you want. When you decide not to call your wife names (frigid or MOM mode), and recognize that she is a human being with faults and struggles like everyone else. When you own up to your faults within the marriage. ETC.
But what is happiness except the simple harmony between a man and the life he leads? ~Albert Camus