Maybe not straight away, but if he met someone a couple of years later and love blossoms, he may feel differently.
Even if he was content not having anymore kids, he may find that unless his new partner already has kids, it would be a dealbreaker and he has kids to keep the relationship.
It's either:
he has stepkids and some men don't want that
he gets with a woman who doesn't want kids, but is happy to be a stepmum
OR
be agrees to become a dad again with a woman who doesn't have DC
A lot of older dads with kids from the first marriage/relationship would be fine without more kids, but men being men, means a 50 year old man can get with a 30 year old woman who doesn't have kids and wants them.
She can present as a great stepmum with lots of energy for the kids and that's hard to pass up for some men. Especially those who relied on their wife to do most of the childcare and domestic work.
It's why there's a lot of conflict between stepmums and mums, because the dads pass on their parental duties to the new partner. You barely get stepdads moaning about the stepkids dad, because they leave parenting to their partner.
Men/dads on the hand, rely heavily on their new partner for childcare, pick ups, preparing meals, laundry etc and there's a shed load of women willing to be in this position to get a good man, because the single ones without kids (at a certain age) are rubbish, so they settle for being a SM.
This went a lot deeper than I intended, but I see it a lot in my line of work.