Go for the 50-50. I have seen numerous studies indicating that is what is best for the kids as long as both parents are wanting to be involved in their kids' lives. You seem like a good dad that is willing to make the necessary adjustments and sacrifices to give your kids what they need and want...
I'm just guessing here, but I think your W wants a greater amount of time because she wants a bigger check from you for child support. She's using the kids as an excuse to not work and wants you to front the bill. In her mind, she would rather have the kids and work one day a week than for you to have them half the time and have to go out and get a job...
Me: 38 W:31 Kids: S16(mine from previous R), D10, S9, S4 M: 10 years T:12 years BD:Jan 3, 2018 W moved out: Apr 13,2018 Filed for D: Jun 2018 D final: Sep 2019
