You are doing the right thing. It is wonderful that you are trying to save your marriage. Labug is right you can not control your wifes decision, but you can weed the garden daily - encouraging the flowers the bloom.
Having two kids so young and close in age is tough. Trust me I know. Plus your W is going to school, plus dealing with two huge deaths in her life. You should read "The year of Magical Thinking" by Joanne Diddon - its about the death of her husband. It may be something you want to pass on to your W after you read it.
I wouldnt read too much into her feelings for high school boyfriend. I think its normal to fantasize about that kind of stuff but it doesnt seem like she is acting on it.
Your W has still not left the house - count that as a big plus that she is giving you time. I think you should do something dramatic to show your W the new you in terms of spending time with the family. You travelled the weekend of her brothers funeral that is not cool.
Can you talk to a supervisor about your marital problems and have an assistant coach cover for you during 1 or 2 practices a week? You need to show her that she is more important than your job even if it means that you are not as good a coach as you can be. She needs to know that she & your kids come first not the team.
Look at professional coaches families - Tony Dungys son committed suicide, Andy Reids sons have drug problems. The hours and time away coaching take its toll on everyone in the family. Show them that they come first. Remember you will need to sacrifice something to give them more time.
Keep it up.
---- M 39 H 35 D5,D4 M 4 T 9 ILYBNILWY 5/18/11 Left 7/11/11 Divorced 12/1/13