I agree the "doesn't understand me" part is bullshit, but be careful about the other assumption. A TON of married women, once their husband is successful and they have a few children basically "shut down" physically/sexually. You'd be suprised at how fast that ambitious, wide-eyed flirtatious 24 year old turns into an entitled, benz-driving, lunch-hopping, social-climing 40-something. The "horse that got you there" (husband) can quickly become excess baggage that mopes around the house begging for sex all the time!
I've seen it happen to pretty decent guys too. That's usually what gets them off straying.