Where I live (in south florida) the "always siding with the mother" is rare if the father is requesting 50/50 split. Any good divorce lawyer can put a decent effort to have that accomplished. As for child support, if you have 50/50, it will more likely be alimony if you make more than her. Many divorcing spouses are willing to split income and kids with a post nup rather than have a nasty court fight that has the potential of loosing. Unfortunately, this requires you both to put petty differences aside and focus on the kids.
My current "trial separation" is not intended to give us space to get back together. My Ex and I are using the trial separation to create and test various forms of custody and financial sharing. That way we can talk things out and come up with realistic expectations for finances.
For example, I pick up the kids on Wed night after work. We all (including my ex) have dinner together and then the kids come home with me. On Sat night we have dinner together again and she keeps the kids. We would do week on/off, but splitting the week seems to work better for the kids and give a nice consistency. As for finances, both our incomes go toward mutual bills (rent, shared credit cards etc) then we split what is left over four ways. 1/4 goes to her personal account, 1/4 goes to mine. 1/4 goes towards the kids and anything else that is mutual. The last 1/4 pays off extra any of our mutual credit card debts. The plan is once the credit cards are paid off sometime early next year, we will create an alimony plan that we can both agree with.
However, keep in mind, we both hold out hope that we can repair our marriage. However, we are both realistic that it is not likely to happen and we might as well both do what we can for the kids. The argument to trial separation was simple... She makes me unhappy and I make her unhappy... Therefore, if we truly the cause for each other's unhappiness, then trial separation is a logical and simple way for us both to be happy again. As expected, I am happy, but she is not and refuses to address what her real problems are, even though she can't blame me anymore since I am not around.