You assume, without evidence, that his kids are troublesome. You overlook that they could be perfect angels, but that he still feels they are a larger timesink than he would have liked. You validate the taboo: he dissents, so your immediate kneejerk reaction is that he must be a bad parent with unbehaving kids.

Here's a thought: one can be a model parent with model kids and still feel that life without kids would have been better. You can even enjoy your life and your kids while still feeling that way.