Oh, Harvestdream, what a difficult, hard time for you. No way to really help with the childrens' reactions on you being with their dad, their dad not being with their mom and you two marrying.

I have three stepsons, only one of whom was under 18 when my husband and I were first working together toward marriage and his divorce. The older two were high school grads, still older teens but not as influenced.

I would see if you could do some things with the daughter, just you and her, when she is visiting? Let her get to know you some? Maybe the two of you run out to the grocery store after planning a meal? Just get to know her some on the weeks she is with her father.

When we married and the young son would come visit, the three of us would go on vacation but I would give them a lot of space for father/son sorts of time/vacations. I did not force myself on his son, make rules or otherwise try to influence his behavior except for how it related to me, personally (we got into a bit of a shoving match in a hallway when he got a growth spurt as a mid-teen and I pointed out to him that "you may be taller but I outweigh you by about 100 pounds" :-) I did not let him disrespect me. But if I did not like some of his behavior, I would discuss it with his father and let him address it if he wanted rather than make an issue.

Your boyfriend's children have two parents and don't need a third. You also are not a "friend" though, either. Relate to them as "yourself", a mature, caring, adult to a child and it might go the easiest? You cannot help with what they do/do not tell their mother about you or what she does/does not think of you, how she behaves, etc., you only have your own thoughts, feelings, and behaviors to guide you.

You can express your sorrow that the child is sad about the breakup and ask her what might make her feel better this moment. Helping her learn to live in the moment, not automatically resent being with you because you are not her mother or be sad her father is not with her mother, etc. is probably the best you can do for both of you. If a situation gets difficult, change the subject as one does with children, it's a distraction against sadness and loss which is true/there and there is nothing wrong with distraction at those moments if there is no other way to help a person feel better? You are not a mother or therapist, just a caring adult. The relationship will change and mature over time; I am fine friends with my three adult stepsons (and their mother!) since beginning this life path in 1985.