Just got information that indicates XH and OW have broken up!!!

Now, I need lots of help with what to do next. I want to do it exactly right. I think I should just pretend I don't know that, not talk to him, basiclly keep things the same, yet now I am more determined to be happy, light, fun-loving when we do talk... about the kids. I did do just that last night when we did talk, about Thanksgiving and Christmas. I just don't want him to get a new OW!! I want to be the new OW! What should I do??

A

Me-40
XH-44
T-21
M-18
Div-19 mo.
D-18,S-15,D-11
Bomb-7/07 EA,PA
Mvd out-9/07-to give me space
mvd back-12/07
mvd out-7/08
back with OW since 2/08
OW broke it off-1/10
in and out of tunnel and our life since!!