Sister in law having a baby

Ok so today my sisTer in law is having her baby everyone is so excited and im happy for them but just because of the fact i have been with my so longer and trying longer with no success is kind of downer im wishing it was me.. My fiance doesnt know i feel this way and constantky talks about it would it be rude to ask him to not talk about it so much cause i feel this way or get over it and keep it to yourself