Ok, so two of my bridesmaids are my two cousins. One is 13 and the other is 18. Their biological parents divorced when I was VERY young, and I have not seen or heard a word from their mother since, as their mother lives about an hour and a half away, and since she's not a blood relative and the marriage ended badly, my family doesn't have any ties with her other than seeing the cousins. They live with their mom during the week and their dad every other weekend, which is the only time I ever see them. Since then their dad remarried a wonderful woman. I was planning on inviting their biological father and his wife, along with them, although now I'm wondering if I have to invite their mother too- Is it weird to invite a 13 year old without both of her parents, or is just her dad and his wife ok?