OCD advice

i myself do not have OCD but my fiancé does. i want to find ways i can help him if at all possible. He’s having a really hard time and it’s affecting absolutely everything he does. he’s told me he cannot make a single decision or move without an obsession being attached to it. It’s affecting the way he eats, sleeps, acts, treats me, goes about problems in our relationship, etc.. and i do understand why it’s happening. he has a lot of stress which triggers his OCD which triggers his stress so on and so on and so on. it’s just one big cycle. he was on antidepressants but has stopped taking them so i’m not sure if that affects the way he copes with OCD. I never tell him to snap out of it, never tell him to get over it or anything like that, never enable it either. but my question to you all is what can i do to help? to understand and support him? is there anything i should know about being in a relationship with someone who has OCD?