middie, i think you need to be really careful to not let yourself believe what you want to believe over whatever the truth of this situation really is. i have no idea if your fiance cheated on you but it sounds like this is just his father guessing as to what caused the breakdown. it doesn't sound like your fiance told his dad this is why he broke down. i am very concerned for you because this man knocked you over at 8 months pregnant and drove and walked off. please do not be in a rush to take him back until you know the full story and he takes responsibility for his actions. what he did to you is quite serious.