She's scared to death of him. She's considered leaving before (remember her standing on the Four Corners Monument?), but is too afraid.
Of course she's tried. She even got them over to her sister's for a while.
Maybe YOU don't think she's playing the part well. Apparently the creators don't feel the same way... Nor do those who nominated her for an Emmy.
I'm not sure what you think Skylar should do. Of course she hates what Walt is doing, and the danger he's put the family in. But he's too deep, and she just doesn't have many choices. Especially considering the predicament she (and Ted) got herself into.
1) She didn't try. She faked trying. If she tried she would have gotten away and been caught. What she did was like a "suicide" attempt where the person holds up a knife to their wrist for 2 seconds and then puts it away without making a cut. She had the motive, the opportunity and the financial freedom to escape and WILLINGLY went back. And you call that trying? ROFL!
2) Yeah, she had the kids away. And she brought them right back to live with a person that she's afraid of? Seriously, do you even listen to yourself? If she wanted the kids away from Walt they would BE away from Walt. Again, she had the money and the opportunity to get them completely, 100% safe. And again, she WILLINGLY took them back into the home of a known murderer.
3) She's nominated on the coat tails of Cranston, Aaron Paul, Vince Gilligan and the show. BB has so much buzz at the moment that the freaking M-60 in the trunk would have gotten nominated if the Emmy Awards had a category it fit into.