The problem with posts like this, and it’s not a slight on anyone here or indeed the OP, is that we only get to see one side.
You say he is sensitive, and your reaction to that, in your own words, is to call him ridiculous, and to say he should grow a pair.
That can come across as incredibly callous and dismissive of his feelings.
When someone is sensitive, it’s often the silliest of things that push them over the edge.
The other side of that is it can be incredibly difficult to deal with someone who is sensitive. You end up like you’re walking on eggshells with them.
OP, you said that he’s been this way for a while. Bickering, etc. Yet your baby is 7 months old. How long has it been like this? Before the pregnancy?
In one respect, it doesn’t sound like an ideal relationship in which to bring a baby. You are both to blame for that if that’s the case.
He says he will be 50/50. Ok then, then that’s what you have to agree on when you split (you will split up - that to me seems inevitable.
I genuinely wish you the best outcome, for you and your baby. But that comes with a caveat that is important., I genuinely wish the best for him and his baby as well.
Both of you. Sort it out once and for all. Be the mature adults that you both need to be for your child. In your defence, that is something that he needs to hear more than you, seeing as you are the one currently at home with your child, while he has walked out to go to a hotel. (That action of his alone, without considering the nuances, doesn’t bode well for him.)