She has been Inviting me to all outing with kids, to the park, zoo, anything, she wants to go as a family, usually on days she has all of them... I know she gets stressed out with them all.
What does she think she's going to do if your marriage ends?
SHE NEEDS TO LEARN TO MISS YOU, and to learn to deal with being a single parent. If you continually "rescue" her from these opportunities to struggle, you are doing neither her, NOR you, any favors.