I couldn't trust him anymore. He should have said he doesn't want any more children and let you decide whether to stay with him.
This! This, this, this. It's fair enough his body, his choice. Fine. BUT he wouldn't have told you had you not found out and confronted him, so he'd have strung you along, potentially for years, until you were no longer fertile and take your choice from you because what he wants is more important.
If you really want another child, even to go out and try for one, even if it doesn't happen and then you can say, 'Well, I tried!' then staying with him in a no brainer. He lied by omission, a big one.
Love is respect, and if you don't love and respect yourself first, then I can guarantee no one else will. If he loved you, he'd have been honest with you about never having any more kids (and I can see his point, I think it's a bad idea to have a kid with every 'partner' in your life), he wasn't. He chose himself first.
Staying with him would be foolish. First of all, no more kids. Secondly, he'll think, Got what I wanted, what else can I do? She'll never leave me.
It's only been a year, I'd not invest anymore time in this.