Is it too late to tell my bestfriend her husband is a dog?

Three years ago, My bestfriend married what she thought to be the man of her dreams. He was my husbands good friend from college and we introduced them at a cookout. After they had dated for a year my husband informed me that his friend was also dating someone else besides my friend. Being the good friend that I am, and feeling guilty for hooking her up with this two timing dog I imediately informed her. She brushed it off and said she was already aware and that he had ended it with the other female. On their wedding day my husband texted me and told me to immediately meet him in the reception hall. There he informed me the my bestfriend soon to be husbands ex was sitting in the church and she was pregnant. I was in utter shock and I had no idea how to handle the situation. Not wanting to ruin her day I kept my mouth shut. Mr dog must have spotted her in the pew because he was stuttering and sweating bullets . Luckily the female remain quite and the wedding went on without incident. Every night I am laden with guilt because I know my bestfriends husband is scum and has a secret family she know nothing about. At this point I feel too much time has passed for me to say anything. But the more I see him it makes my skin crawl. Also to add insult to injury you can clearly see the other female in the wedding video. Was I wrong not to say anything and is it too late to tell now?