Although you clearly love these children very much - the issue they are suffering with is the 'relationship' between their parents - I'm sure your husband isn't happy about the situation but he is their father, his children look to him for honesty and unquestioned love - has he spoken to them about your relationship and assured them that you had nothing to do with it, that he made his choice to move on and if anything you were his light at the end of the tunnel? 

Has he also sat down and confronted his ex, made her realise just how her behaviour is going to affect their lives, not just not but well into their adulthood, as well as the decisions they make as parents themselves?

Sounds like this woman needs a rude awakening - good luck with it, I hope it works out for you, you sound like a lovely woman!!!

wow, sounds like hell with a capitol B.... i think you and your partner need to sit down and just talk about how this women is trying to come between you both, not agure or debate just talk and realise she's winning buy you both fighting about it, so you need to show a unitted front with her... i know harder then it sounds. I would go for full custody , it would be a battle but it always is and it sounds like this women isn't going to stop, so it might be harder at first but in the end geting full custody will be easier on the both of you. good luck.

I believe you are lucky to have such a great relationship with your ex - it's good for your peace of mind and great for your kids to see that just because you love other people now, doesn't mean you can't still have love and respect for each other.  After all, you loved each other enough at one point to have children together!! 

It's hard blending families, and it takes a lot of work sometimes.  But it just doesn't work unless both sides want it to.  Obviously this womanfeels scared or threatened by you.  does she have a new partner?  has she ahd a successful relationship since splitting with your man?  This could ahve a lot to do with her nastiness.

As for your step son, I guess all you can do is repeatedly reassure him that you are NOT trying to take his Mums' place but that you will always be there for him as a friend.

I met my (already divoced) partner when I was 23 and he and his wife did not get along very well.  when we saw that our relationship was going to last we talked about what is best for the kids.  I thought that if I was going to be their step Mum, she and I had to get on.  I talked to ehr about it and assured her that it was not my intention to become the girls' "new Mum" and that no one could ever be her.

Thankfully, she told me she trusted my judgement and that I was free to discuss parenting issues with her any time I needed to.  It was great because on about 3 occasions the eldest said to me "You aren't my Mother and you can't tell em what to do or punish me".  so I would say "Well lets ring Mum and tell her what's happening and ask her what she thinks".  End of conversation, and conformity from Ms 6!!

When I fell pregnant with my first child the girls were initially excited, then the eldes became a bit withdrawn.  I asked her what was wrong and she eventually told me that she was scared once her Dad had a new baby there would be no time or love for her!  Poor little angel.  it made me cry.  I asserted that she was Dads' first child and even if he had 100 more, no one would ever take her place in his heart as becoming a parent for the first time is a huge event, never to be forgotten.  we talked more about why her Muma nd Dad didn't love each other, and I explained that it sometimes happens, and that there is a big difference between being "in love" with someone and "loving" someone.

Thankfully we have weathered the storm of blended families, and shared many parties, BBQs and family get togethers over the almost 18 years since I met my partner.  I call my stepdaughters "my big girls" and they ahve a very close and loving relationship with their yonger half brother and sister.  My stepdaughters are now 21 and 24 and we are very close - sometimes I am even surprised at what they share with me!

Good luck - I really feel for you!