If the others created a list of the most vulnerable people they know, Fyodor would most likely take the last bullet.

However, those would only remain as mere assumptions when he's with his lover; you.

Right now, Fyodor laid beside you on the bed you both shared every night and day, head buried deep in your chest, your hand running through his hair. His eyes peacefully shut, his face relaxed. In most cases, you'd know yourself that you really are the only one who does it how he likes.