In future, don't let anyone near your child for a long while. I'd aim for at least a year. There's no reason a man you are dating should be a father figure to your child. I get that they may meet in passing before that, but he doesn't get to buddy up to your son until you've dated a lonnnnng time.
What your child needs is a happy mother, free from the manipulation and abuse of bad men.
Bare in mind in future, whirlwinds are usually not healthy. Healthy relationships grow organically over time, they don't push you to rush feelings or intimacy.
As for this guy...be aware that when you say this just working for you anymore because you clearly don't want the same things, he will likely backtrack and say he wants the intimacy. Or he will bold face lie and say you misunderstood him and he always wanted that. Or, he will try and convince you that it's silly or unfair to throw away what you have over this. Or that you should stay friends.
Your needs in a relationship are not to be disregarded like that. You were the one who went into things in good faith before he changed the rules. It's not you that's ended things, its him. Hes changed the dynamics to something unsuitable. You don't owe anyone a relationship. Let alone one that doesn't work for you.
And your needs are not silly. They are valid.
But it's best not to be drawn into debate with him as you'll only get gaslighting.
Just give it 'I've enjoyed your company in recent months however its become clear we are both looking for different things'.
If he pushes, simply reply, 'this is no longer working for me, I wish you all the best in future but let's draw a line under things here'.
It's perfectly fine to end it by text. But if you must do it in person, do it in a public place with people all around. Do not let him back in your home.
Once all is said and done, you'd also be wise to block his number.
Ps: don't beat yourself up. You have spotted it now. Dont doubt yourself. Normal people don't push for a relationship and then once in it go 'oh yeah so btw I don't want sex anymore' and then think the relationship can just continue as they want - as if it doesn't totally change things. I mean like, what the actual fuck mate? It's not normal to drop a bombshell and expect everyone to just shut up and be cool with it. It smacks of them thinking only their needs matter.