I hope you don't feel ganged up on here, but you have to take a look at the situation that is established. She met her husband long before you and her attachment is deeply rooted, whether she is unhappy or not. While she continues to have fun and live the lovey dovey things with you that she is probably lacking in her life from her real husband, she still goes home to him every day. She still sleeps with him, although you get an earful of how it's because "she feels bad." Of course she feels bad, and she should: she is cheating on him. Somebody that breaks the vows of marriage for something that is fun and exciting now, but she doesn't know where it will go with you and that is why she hasn't left her husband yet. While you feel you are in love with her, I think it's safe to say that she isn't in love with you. Her feelings for her are not nearly as strong as yours, she has a married life holding her back while you do not.
Giving a year, setting a time table, she is doing this just to keep you there and keep you strung along. She doesn't want to be alone and if she were to make the transition from him to you, she wants to make it as smoothly as possible. Currently, she doesn't know how she feels for you and she's definitely not ready to commit to you. She would have otherwise. You have to take a look at her actions, and no amount of pressure on your part to get her to divorce her husband is going to get you what you want. She chooses to stay with him, she chooses to lie with him, I wouldn't be surprised if the suspicions on his part are starting to build. If he catches her and calls it quits, the woman you would have after wouldn't even resemble the woman you "have" now, she'd be crushed and hurt to have that attachment just broken like that. And that's if they don't reconcile.
It sounds like she has such a victim like mentality. She's stuck in a horrible marriage and there isn't anything she thinks she can do about it. There sure is, she ends it. Before it gets to affairs and cheating. She's too attached and does not have enough self worth to stand up for what she believes in, if she even believed in what you guys have. She's too scared of being alone to the point where she rather suffer. This is a woman you fell in love with and I'm sure you think you can marry? No, she needs some growing up to do. And that won't happen if you catch her when she falls. You have to leave her be. If this is what she chooses, she can't have both you and her husband. Do yourself and her both a favor. Break it off.
Waking up next to a beautiful girl,
Step outside and say hello to my beautiful world.