you absolutely do not have to share all private information with your partners EVER

Your privacy is yours, that is something valuable. Dont let anyone make you feel less than over a little picture you didnt share before. This also applies to anything private in general.

Yes it might be painful right now that you had to see what you saw but months from now or even in a years time you’ll be so grateful if you made the choice of breaking up if it feels like the right choice