Do You Tell Your Spouse EVERYTHING?

I overheard a conversation yesterday between two ladies at the store. Idk what they were talking about specifically but one of them said, “And that’s why I don’t tell my husband sh*t that he doesn’t need to know”. This is the third time I heard someone say something like that. One of my friends told me that I shouldn’t tell my husband everything and even my mom said it (while I was dating). I feel like I’m missing something, because I thought the spouse was the one person you should be transparent with. I tell my husband damn near everything except how much I spend on fast food.

So ladies (or gents) do you tell your spouse’s everything? And if not, what do you keep to yourself? And does keeping things from each other (not necessarily secrets) help or hinder a marriage?