Well, I think it's better to show her how positive and happy life with you and her family could be rather than telling her. Actions rather than words are way more effective.
I do think you may be right. I think no troubled marriage is just on the shoulders of one person. She probably does have issues to work on like depression. She shouldn't be looking at you to fill her life or make her happy, and has to learn how to make herself happy. I think you can and should do that whether you're married or not.
I do think you will probably need to be careful and work hard the rest of your life on trying to maintain a balance between work & family. Something you just have to be aware of. I'm prone to depression and know that I will have to work on that all my life; doing what I know needs to be done. Like someone that needs to lose weight--you can't just do it for a couple months and expect to be healthy forever, it takes long-term effort to stay healthy. Karen