Willing to spend $10,000 on a retainer plus additional associated costs are a lot of money to keep a couple hundred bucks coming in every month. Any harried parent is known to make comments about a few months break from parenting and fantasize about the single life occasionaly.
I don't know your case, so I am not saying what you tell us is not true, per say, I'm just saying don't assume the examples you are giving to change custody will hold up to well in court.