I’m worried my partner might be hiding something on Facebook and I want to check their messages without them finding out. Is there a way to do this without them getting notified?
Logging into someone else’s Facebook account without permission isn’t really a monitoring app thing - that’s just unauthorized access to an account, which is illegal pretty much everywhere regardless of your relationship.
If you’re worried about your partner, honestly the most practical move is a direct conversation, or if things are really bad, couples counseling - no app fixes a trust problem.