The cooking situation was more to do with me cooking shopping and meal planning everyday despite working full time.when I brought this up partners answer was he will shoo and cook separately. What i wanted was some help.
From his POV, he probably doesn't want the stress and hassle of cooking for 6...so now he just has to worry about him and his DS...which doesn't leave you doing anymore than if you lived with your sons.
You wanted help with cooking for you and your kids...his stance was to take the extra work off your hands. You said earlier that your DS can cook (and his can't), so that should lighten the load for you if that's the case.
My DS is a bit younger and I don't think he would have been able to hold that much exciting information in.
Which is why he should never have been privvy to that information...especially if he's an honest sort of boy.
Keeping a surprise is nothing to do with honesty FFS... wrong is wrong and doesn't need defending like this..but it was the responsibility of the OP not to divulge this information.
By telling her son, she showed there are 2 camps in the house and drawing it to an end is best for everyone.
I would also end a relationship if I felt I couldn't trust my partner...especially when there are no shared DC, if money wasn't an issue and where it has been rocky for a while anyway. This would just be confirmation that it's not working.
He could have decided not to end it and withhold information he doesn't want leaked in the future, but what's the point of that kind of relationship where you can't trust your partner.
Even if your DS didn't say anything before Christmas, if I was your OH and found out you had told him, I'd still not be impressed about it....because I'd be wondering how many other things you'd shared with him and wouldn't believe if you said this is the only thing.