we were due to get married next year and i think shes worried that her family will influence her when they find out about my kids
Either she's young, naive and doesn't really know what she wants, or if she is a bit more mature it's an excuse. A mate of mine's Polish fiance broke it off with him because of parental pressure (in this case it was because his background was from the Middle East part of the world, even though he wasn't Muslim). In the end he persisted and they got back together, married, had a kid, etc. In that case, it really was a question of family pressure. It your case, it might not be, since she hasn't even told her family yet.