Not sure if this will help, but I found myself in a similar position over the last couple of years. New business partnership going well, six great kids, loving wife, but really not any drive and/or appreciation for what and who I have in life to be thankful for. My son was recently involved in an accident and he may not regain sight in his right eye. Not anybodys fault, just kids being kids, and I am afraid for him. I have never prayed so hard for anything in my life, and he still has a long road to go with much healing and possibly more surgery if the eye shows some promise over the next couple of weeks.
I guess my point is maybe when we become complacent/lukewarm as you say, maybe things like this happen to let us know we need to be more thankful and energetic about who and what we are. Maybe this is psycho-babble, but your post rang a chord with me, so I thought I would share. give those kids another hug tonite and do something special with them this weekend.