Cheating husband

So I need some advice I am currently 8 weeks pregnant I found out yesterday that my husband who I married on July 15th of this year could possibly have another child that was born on Dec 28th it was a total blindside I literally thought I had a damn near perfect relationship but come to find out he knew she was pregnant when we got married an whem he begged me to have another child! We are also a blended family I have a son who is 10 an his son is 8 which i have legally adopted his son. We are waiting on the dna papers for the appt so that can get done now but I was wondering if anyone has ever been threw anything similar? did u stay with him? could this relationship work if it is or isnt his??