How long has he been your roommate?
And has this ever happened in the past?
things me being, you may want to put things of santimental and monetary value to you in a safe place. A person can work on controlling their symptoms. Yet, you don't want to wait and see if it happens. You may want to ask him what steps is he going to take to work on this?
Is he going to consult with a therapist or perhaps his physician for antianxiety medication?
Giving him a chance is the decent thing to do.
Individuals w/ OCD really feel out of control at times in restraining their impulses (obsessions/compulsions) With a rise in anxiety level, you may note an increase of these behaviors on his part.
You could take a card board box and label it "things to check" Place it somewhere that he can see it and tell him that if he has the urge to throw away something of yours or your partner, to place it there first for your inspection.
I'm not sure if you're online now. Feel free to reply.