Husband spying on my phone?

How can you find out if your spouse installed spyware on your phone? I’m getting this feeling that my husband might have, because I’ve been logging events/feelings in my notes app. I’ve also sought out advice regarding my relationship issues online, and how he’s behaved/reacted sometimes aligned with what I’ve typed down or looked up. It’s making me uneasy, and I don’t know how to confirm my suspicions as I’m not tech savvy.