The unfortunate truth is that 'maturity' for women is nothing but a euphemism that masks her biological reality. If she had the same body she had at 22 at 35, where would she be? Fluff words like 'maturity', 'life-partner', 'an equal' yadda yadda, all of them would be thrown by the wayside in not a moment's time. And they often are tossed aside by women who don't give it up, when you look at the Eat, Pray, Love divorce narrative mid 30's women often follow.
Not to be rude or insulting, but all of those words you use to describe your relationship: loving, caring, maturity, yadda, all of them can be thrown away to satiate her hypergamous impulse. In ANY relationship, whether it's hot sex with a 22-yo or a LTR with a 45-yo, you never think of them in terms of those words because the notions they describe are rooted in idealism and don't exist in reality.