Relationship with the ex

It has been about three years now since she (the ex) decided "it wasn't me that bothered her, just my husband (her ex-husband). So all those times of bickering and stupid comments to each other to see who could be the meaner are in the past. I would never have thought we could get to this point, but it happened. While I still do not agree with everything she says or does, I am perfectly capable of picking my battles and biting my tongue when it isn't important. Now I find myself in the situation where she took an e-mail I sent to her informing her of the plans we have for the graduation party for my step-son as an invitation to attend my party! How does that happen!? Well, after much thought and a little panic, I decided this is what it is all about. Getting together in peace for the sake of the child. I cannot lose here. I "invited" her to attend the party I am planning - makes me the bigger person. Anyway, we'll see how it goes...