After reading some of the posts on the Relationships page it seems that:
Dad gets bored with tedium of parenthood
Dad leaves and starts exciting new life of freedom
Mum gets left holding the baby, short of cash, trying to juggle work and childcare/chores.
Have any mums considered being the one to leave instead? It sounds much easier to pop by at weekends and do fun stuff with a child who is fed up with the exhausted, frazzled parent at home.
Granted, for couples where there isn't the same earning capacity or where the dad is abusive etc that isn't possible. But what about couples where both work, both are capable of being the primary carer?
I'll be advising my dd to stay financially independent and never, ever to have a child with a man she doesn't think is capable of being a primary carer. I really feel for some of the posters, they've been royally screwed.