what a horrible dilemma to be in.
You have some insecurities about H's penchant for hanging on to memorabilia of old gf's and his porn use - I'm not surprised. These are inflamed by his use of dishonesty as a means to protect himself.
You then feel compelled to use a kind of deceit to search for even more evidence of his. You then bottle it all up and feel upset that your relationship is based, at least in part, on lies.
These are not petty lies, OP. They are not petty because you have been unable to ignore their impact on you. They are not petty because they prevent emotional closeness between you and your H. They are not petty and they are not about an old book - they are about the fundamental requirements of any loving relationship - honesty, mutual respect and a genuine desire for the other's well-being.
You have choices here. You can continue to live like this, insecure, suspicious and, I suspect, feeling ashamed of what you are driven to do to keep on the same page as him. You can confront the issue of his dishonesty head-on and risk the unknown. You can (if you haven't already) get yourself a good therapist and explore what you might be re-living in this relationship which seems so resonant of your childhood experiences.
You don't have to put up with this OP. You are not paranoid you are rightly and justifiably hurt and dismayed by your H's behaviour. I don't know anyone (myself included and i'm pretty broadminded) who wouldn't react in a similar way to you.
i really feel for you. I hope this helps.