Broadsided

I'm at a loss. Today I returned from the shop after a hard day of work. Mary seemed rather flustered and when I asked her what the matter was, she responded that she was pregnant. I know for a fact that I am not the father and I am confused as to what I should do. I love Mary with all of my heart and I am completely devoted to her but I feel betrayed and broadsided. Unfortunately, I find her story hard to believe. She explained to me that she also has honored chastity. I don't want to accuse her of lying but I know that there is no possible way for her to be pregnant and honor chastity simultaneously. I feel broadsided and don't know how to respond. What would you do?