You've got a couple of options.
Get right back on plan now. Not tomorrow, not Monday, now. Draw a line under what you've just pigged out on and get those speed foods on your plate.
Do the same tomorrow and stay on plan and make something else rather than the pizza.
Another option is to get back on plan today as above, and stay on it tomorrow, but flexi syn for your tea. Decide on your limit of Syns and once you hit that number, stop and switch back to free foods. And don't reduce your Syns on any other day, go back on plan as normal.
You could always tell him how you feel about the fact he has bought something and not really considered you and what you are trying to achieve by following SW. But I know they don't always understand, I've got experience in that lol, but maybe if you talk to him about why you are doing what you're doing, he might resist tempting you with these kind of things.
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