My xH is 5 years older, but this question has resonated with me.
xH always seemed to like older women; in fact, when I met him, he was madly in love with a classmate of ours who was one year older than him, and also a mother already. I think he adored her maternal image. She is blonde, too, like his ideal, and like his birth and adoptive mothers.
I think maybe my youth was a drawback for him, especially when I would act all giddy and girly around him. He would get very irritated. He wanted me to behave more like his mother, I'm certain of it. He criticized my mothering until the day he left, then suddenly had a change in his tune--I was a good-enough mother after all, and the kids would do well under my care.
xH named his first sailboat after his still-alive mother. I was pretty turned off by that, frankly.
xH's OW is two years older than I am, but she has no children of her own. I've suspected that she mothered him--knew just how to manipulate him. She's from a "nurturing" profession, like many BPDs are. I doubt very much that she nurtures him now, if I am to believe what I've read about BPD OWs.
Before BD, I'd been growing seriously distressed with and confused by xH's increasingly childish/feminine mannerisms and was at my wit's end--I knew I did not want to be in a relationship with a child--I wanted a partner who was my equal, a real man. I didn't know what to do, as I was very much committed to my marriage and family. I honestly felt trapped in an unhappy marriage, and my immediate reaction (albeit very short-lived, on the order of several minutes) was relief.
I know I have daddy issues, having grown up under the thumb of a very controlling father.
I'm sure this created conflict between us. There was always huge friction between my xH and my father--created by my xH, probably because he felt I was expecting him to take on or submit to (both unfair propositions) my father.
Yeah, I do think sometimes there's a mommy issue, but of course age is not the only factor. I think it depends on how the MLCer saw his wife/partner. If he saw her as a maternal figure or wanted to, and took comfort in the age difference, then maybe there is something to this theory.
I'm certain my xH has mommy issues and would have preferred to be with an older or more maternal (toward him) woman.
To love is to value. Only a rationally selfish man, a man of self-esteem, is capable of love—because he is the only man capable of holding firm, consistent, uncompromising, unbetrayed values. The man who does not value himself, cannot value anything or anyone. --Ayn Rand