Kim Kardashian and Kanye West are doing their part to co-parent successfully and amicably.A source tells ET, «Kanye and her have been coparenting successfully and both of them want what's best for the kids,» and that their four children — North, 8, Saint, 5, Chicago, 3, and Psalm, 2 -- are «doing great» following their split.The source adds that the two «have been supportive of each other» when it comes to raising their kids after Kardashian filed for divorce in February.«Kim is continuing to