I mean technically, saying/thinking that is absolutely fine. Lord knows there's enough posts on here day in day out of people saying they miss their old life, wish they had more free time, they love their kids but find parenting/the workload boring or overwhelming. Replies stating how they feel it too, can't you put little one in nursery for longer or leave them with someone whilst getting "you time" etc. At least he's honest and not bottling it up.
The issue is how this comes through as Actions, I think? If he's still loving, supportive and involved I don't think it's a problem. If he's distant, snappy and leaving 70% of life to you, not so much!
My DH is a bit like this @Japaneseflower and actually it comes out more after he's had time away. It's like they get a snippet of "old, carefree times" then it's back to reality. It does make me angry when he says things, but if I step back and look at the whole, it's not actually that bad.
We only have one, a five year old boy with autism. I do bed times and night wakes and I'm more on top of appointments, forms etc. But DH comes to any appointments that are essential, he sits with me doing forms and he reads the books/online resources etc. He does bath time and reads stories when DS eats supper every night. He works earlier shifts so I do the school run, which is hard because DS can have high anxiety about drop offs and I need to ensure everything goes smoothly. But DH does pick ups and has him on his own for a couple of hours 3/4 days a week when I'm still at work, which can get overwhelming some days.
Housework we now split pretty evenly I think. When DS was younger I'd say DH definitely did more on that side because DS was glued to me and it took lots of time, patience and strategy to slowly but surely work on that.
I guess what I'm saying is, I know it's hard to hear but there's nothing necessarily wrong with feeling like you wish some days you only had to do 30%, as long as you also accept that's not actually an option and find a way to work through that without it negatively affecting the family.