FI and I are getting married on 12/12/14. It's the second marriage for both of us. I don't have any kids, but he has 3...two girls (ages 6 and 8) and a 4 year old son. The idea was to have his 2 daughters be flower girls and his son be a ring bearer with my 3 year old nephew.
His kids love me, and I love them as if they are my own. They stay with FI and I every weekend, and they always have fun.
He and I are both worried about the girls, especially the 8 year old. She's very smart and understands what's going on. She took it very hard when her father told her about he and I being engaged. (Although FI and I are sure his ex wife put ideas in their heads too. She sometimes can be very good about it and other times be very jealous and spiteful.) It's been a tough situation for her, which I understand. I'm sure I would go back and forth like that also if I were in that position.
We go back and forth about whether the girls should be at the wedding at all. Part of us both think that maybe they're too young and fragile to witness their father marrying someone else, even though they love me and know that I love them. Another part of me worries when they get older that they will be resentful that they were left out.
Has anybody else gone through this? How did you handle it?

