This question appears to stem from a misunderstanding, nonetheless an interesting one.
As an analogy, let us consider women and food. It is well known (I don't mean necessarily true, I mean well known) that women's relation to eating is much more "emotional" than that of men. Women are traditionally the guardians of access to food, they have secret recipes their lovers (male or female!) will never be able to reproduce, they work magic with those cauldrons, and even if men (men as a genre, not men as individuals) have professionalized the craft of cuisine and developed it as high art, it is what is often demeaned as "comfort food" that provokes revelations like that great moment with the food critic in Ratatouille, that raises up the sick and makes grown men cry.
Which brings me to my point. The affinity between, say, women and food in general, and women and cheesecake in particular is also (by the above definition) well known. The angst which rises up around women and diets is, it seems to me, a pretty good analogy with your cheating scenario. If a man and a woman both cheat on their diet, and the woman has more of a communion with the cheesecake, does that make it more serious? Maybe she just enjoys it more.
I think this idea of "women care about emotions in sex, therefore any man they have sex with must be someone they care for" is a backhanded way of complimenting men, meaning, it is really the sort of theory only a man would come up with -- oh yes, obviously whenever we touch a woman with our magic wand, she falls under our spell and is a little bit ours forever, whereas we can gallavant from woman to woman unscathed. I don't think women would necessarily describe it that way. For instance, just because you feel that sex is about intimacy and personal expression doesn't mean you always have more of a personal connection with your partner, or even that it is necessarily about them. For instance, maybe it is more cathartic for you, or a more satisfying self expression.