Fiancés phone

Does anybody else think it’s weird when your fiancé refuses to share his password or even let you see his phone.

I’m not really the type to go through somebody’s phone because I wouldn’t want it done.. not for bad intentions but it’s personal stuff I guess idk.

But I believe in my heart hes not cheating on me and we have a happy family with a 1 year old son that we both love and cherish very much, we live together and pretty much are together all the time besides work... but the phone thing I never understood was he alway says “I don’t need to share my password with you, you’re not my mother and I’m not a child, if you trust me than why do you need to research everything I’m doing on my phone, itsnot that I’m doing anything bad but I just like some privacy”

And I GET THAT, I’m not complaining I’m just trying to see if anybody can relate to the situation that I’m in, I’m not UPSET by it but sometimes it does slightly get under my skin lol cause I’m a curious person , you know what’s going on in that little mind kind of thing.