I hate to say this, but she is more than likely involved with someone or is receiving external validation that is putting her on the fast track to get out as fast as possible. The going out to "the bars and parties" with her "girlfriends" and these actions are usually a sign. It's not 100% guaranteed, but after reading 100's of post on these boards, it's all too common.
You have to remain strong. You are predictable and hurting right now. She will NOT respect you if you breakdown and tell her your feelings or talk about the relationship right now.
You actually need to continue with the gym and stick to your goals you listed. Consistency. Consistency. Consistency.
Now she's leaving you to go out to the bars and your the good husband staying home with the kids and bettering yourself.
Want to try something different? Become mysterious. Fake being happy right now. DO NOT talk to her about the relationship AT ALL.
Go out and get some clothes, like clothes if you were going out on a first date. Casual, but confident. Get some new cologne and tell her YOU are going out with some friends tonight. Don't tell her too much, just get the kids taken care of and go out. Now, I don't care if you need to take a 6 hour road trip dressed nice, but GO. Make her wonder WTF is happening for a change. It will help empower you and it will make her curious. When she asks whats going on or where you went, be vague. Don't lie, but change the subject.
Your going to hurt bud, but you have got to change the dynamic quickly and MAINTAIN your current changes. Is there anything you can think of that you can roll your time and efforts into that you can fit into your schedule with the kids?
Everything I'm telling you will sound like torture to do, but if you want change, this is worth a shot. Just keep your integrity towards your marriage, but don't be afraid to do something outside your comfort zone.
