i respect your opinions. but i disagree with this. i NEEDED our son to be in preschool after we brought our newborn home. it was a tough transition for him (see my post above about him trying to push her out of my arms). and if i was going to relax during my maternity leave and get used to a routine with an additional baby, i needed him gone half the day so that i could accomplish that. just being able to sleep for an extra hour in the morning gave me enough energy to handle both our kids' needs in the afternoon before my husband came home.
him forming new relationships in preschool was exactly what he needed to take his little mind off of any feelings of being cast aside or left out, even if it was just for half a day. had he been home all day with us, we would have had more conflicts with my time-management of two needy babies, me needing rest, me needing to prepare meals, clean, doctor's visits, etc.
my husband only had 2 weeks off after our daughter was born, so after that, i was flying solo. i would have returned to work a mental, emotional, twitching hot mess if my son hadn't had a structured outlet for half the day.
plus, our son had been kept by my mother for his first 3+ years. he was an only child and didn't have enough consistent interaction with other children his age. he benefited from being in preschool at just that time (almost 4 years old).
so on the contrary, i think that him being in preschool was perfect timing for us all.