Immature? You? Most likely since you seem to not understand that relationships are never perfect and usually one of the individuals in the relationship ends up picking up the slack of the other. I and the Mrs are not two peas in a pod. I am tidy, neat, organized, clean. The spousal unit... Well lets say that we are a 'half doer' are best and leave it at that. Also one person is always more dominate than the other in relationships. Its how the relationship will work. when both are dominate the relationship is doomed - Doomed I tell ya, Doooooooooommmmmmmmmmed (Said in my best end of the world voice). In straight relationships it is usually the woman who has the nesting impulse, wants the domestic things done while the guy sits around and is content if the house is a pig sty. There are exceptions (I live it every day). If love, laughter and caring for you very much is not enough then you are in for a world of hurt. There is no such thing as a perfect man (or woman) you get what you get and you be damned happy when they don't hit ya, call you names, drink or use drugs or commit crimes or murder you in your sleep or sleep around on you.

I'm actually in the same situation as you, so I wish I had an answer, but good luck.

Not so much immature (him) as easy-going. You will not be able to change his personality; only he can do that. My ex tried to get me to change myself from an introvert to an extrovert; it was difficult but I succeeded, but even then he was never happy and I started to resent his insistence that I was not good enough for him the way I was. Either accept it and learn to live with it or find someone else more suited to you.