Okay, back story:
Before me and DP met he was married for 4 years. But the marriage broke down due to the fact that his Ex-wife cheated on him (multiple times throughout their relationship). The day he found out she left and that was the end of that.
As far as I know neither of them had filed for divorce by the time me and DP got together. I fell pregnant (unplanned - this is significant) very quickly into our relationship. During the pregnancy we decided that it was time to file for divorce.
At some point DP and his ex had had a conversation about filing and the grounds they would file on. She said she would contest the reason of adultery, so in the spirit of getting it done my DP filed under unreasonable grounds.
Paperwork was sent off but sent back promptly as DP hadn't give at least six instances of unreasonable behaviour 
Due to complications in my pregnancy the paperwork ended up on the back burner and 6 months later she has decided she wants to get it sorted.
Fine by me. They have been separated for two years now, so I'm led to believe it's fairly straightforward.
Today she has text DP saying she has filled in the divorce papers and stated the reason as DP wanted a baby, she didn't and now he's had a baby with someone else 
I'm so cross. She will not take responsibility for her actions and it makes me so bloody mad. I'm tempted to contact her and give her a piece of my mind (unreasonable, I know). I just feel like that cheapens our relationship and makes it seem like DP found the first willing womb!!
Urgh.