Understood. The whole dynamic is so much larger than just this statement tho.
Children introduce pressure and stress. How a couple deals with that pressure and stress will dictate the everyday quality of the marriage.
No gender is at fault here. As
@Ranger has been advocating lately, you grow up with ideals, and you don't realize you are being sold a bill of goods until it's too late.
Story most of you probably don't know: an infant wakes up every three hours to eat. This will occur until you sleep train them after 9 weeks, or wait till they sleep train themselves (usually after 3 months). If a woman is breastfeeding, this means she most likely (because NAWALT) will become sleep deprived by 2 weeks in. If communication is poor between the couple she won't ask for help and she may feel resentful, angry, tired, used, etc. This begins the slide and decay of a relationship. Recoverable? Yes, but it takes work.
Of course there's "more" to every "story", but that's a quick synopsis to illustrate how an infant changes things.
I've long believed that women in society fail young girls (and boys) by not being honest about how difficult having a baby is. I feel that, of we were honest about it, teen pregnancy would go down, mate selection would improve (at least in this area) and better, more open communication of needs would occur between partners.
At least, if the topic of starting a family was discussed from the "that's going to be really hard on us, can we handle it well? Can we come together? How are we going to come together?" Couples might have a better survival rate - and the intimacy/needs that are required to keep boning will be met.