Have you spoken to him about it?
(It’s always ok to not want sex! It’s not ok to feel pressured or uncomfortable, both morally wrong in general and even if you do want to do it sometimes and some ways, pressure or uncomfortable is a turn off)
Twice a week is plenty, without kids! With, especially three of them and a one year old, it’s a lot!
If you would prefer to work it out, maybe talk to him. Tell him some things don’t turn you on, they actually turn you off, so it’s better not to say them that way.
Maybe explain that a text saying «You are so beautiful and hot too, I’m a lucky guy, thinking of you, hope your day is good» is way more likely to lead someone that night or a few nights later and a happy intimate life than something that feels like a demand and pressure, which is doing the opposite.
Saying he feels démoralised, ok he’s saying how he feels, sulking not ok. One is communication, the other is unhelpful, not a way to communicate and upsetting you. If you haven’t explained this and want things to work, maybe explain how you feel?
Also explain twice already this week with a one year old is a lot!