You are the one who wants to change this relationship and I can see the love you have for your boyfriend. For him his duties as a father are more important than his relationship with you. You may have good insight as to where the boy's mother is going wrong but no one in that family wants to confront her or change things. It is not your place to suggest that the boy's mother has bad priorities. I think you should accept the father son package and see if the two of them will enjoy a trip with you. Have you heard your boyfriend complain about being a full time father?