There's 3 types of things you keep from your partner:
1-Stuff you're legally bound to keep secret (classified intel, attorney/client privileged info, medical file of a patient...);
2-Her family and friends are organizing a secret birthday party for her (she'll learn soon enough);
3-Stuff that...
Help settle a 16 year discussion between me and my husband- if someone tells you something in confidence and asks you to tell no one does that mean:
A- You’re not telling your spouse/partner
B- You are telling your spouse/partner unless you’ve been specifically asked not to