because I don't wanna ask Facebook

Bre
So my fiancé has pictures of him and his ex wife of him purposing to her on Facebook and I asked him if he could delete them but he said he is not deleting them that way when there daughter gets older he can show her that him and her mommy were once happy ..... 
 
But I feel like she will no that without looking at pictures like that ..
Am I wrong or what ? 😔