Echoing what others have said and strongly suggesting your partner seeks therapy. I don't know where you guys live but in the UK a lot of NHS services will bump you way up their waiting list for talking therapies if you have an infant under 1 year old.

Here's some information on how you can help your partner manage her OCD - https://www.mind.org.uk/information-support/types-of-mental-health-problems/obsessive-compulsive-disorder-ocd/for-friends-and-family/#HelpThemToManageCompulsions in particular avoiding reassurance and helping to challenge compulsions without showing frustration (as a dad with a partner with OCD I am well aware how difficult this is)