I Caught Him Fondling My 8 Months Old Baby's Vagina

I didn't know that Mark was a pedophile until last week when I caught him fondling the genitalia of our 8 month old daughter. I screamed on sighting him, then he withdrew his hand quickly and walked out of the room. I took my baby to the inner room and discovered some red patches all over her after a thorough scrutiny. 
I've felt very cold all this while, I no longer feel safe in my marriage as I fear for the future of our children. only God knows whether he also molests our two year old daughter. 

Pls other mothers out there, have u experienced a similar event in ur family? Do u think there's a solution to this problem outside praying and fasting? I have seen occasions where a father impregnated his own daughter. 
I want to keep my marriage, but I dnt know if I'll be harming my daughters if I continue living in the same house with a pedophile. i no longer feel my daughters are safe.
Pls if u know any practical measures I can take to keep my daughters safe do tell me. I dnt know if this is part of the worse I vowed to endure on the day of our wedding. I can't bear to imagine my innocent girls being exposed prematurely to sex by any adult, and worse still their own father.