What age to tell children 'big things'?

[xmasmorningpaper]

A christmas name so this can't be easily searched against my normal name. :)

I am very unsure how to introduce certain topics to dd. She is currently 2.

The main subject that I am unsure about is that DH and I were both married before to other people, and, to complicate things, my ex-husband had a sex change. Dd knows my ex-husband as 'aunty Claire' and she is a part of our lives. I think that Claire's opinion would be that she wouldn't want DD (or anyone) to know about our past, but I want to be honest with her about it because I think it will MESS with her head if she finds out when she is 14 that mummy used to be married to Aunty Claire.

I have no idea what the right answer is to this. DD has seen my wedding pictures (she looks through our photo albums sometimes) and obviously has no real understanding of what it means that we used to be married - but I don't want to 'cover it up' and DH and I occasionally talk about our ex-spouses. DH's ex-wife sends dd presents on birthday etc, and so far we have just described her as 'daddy's friend'.

How have other people dealt with telling their children about previous marriages (or complicated ones!)?

and fwiw kayleigh my husband is very difficult aswell!

SantaFio2, it's a hard subject to bring up isn't it. I think my ds1 is ready but unfortunately his best friends dad walked out on the family this summer and I don't want him to think that men do this willy nilly and that my dh might move on to another family IYKWIM.

My dh is great - he is just completely stubborn about this subject. Probably because he considers it in the past. We don't live in the same town as his ex or daughter but we do visit his family there a couple of times a year. It is very possible that someone could mention something in passing. i would hate ds to hear it from someone else.