Custody

I am contemplating divorcing my husband, however we have 3 young children (4-8 yo) and I am concerned about the posible custody arrangements. I have taken maternity leave wih each child and remain home part-time. I work 2.5 days a week and make sure I am home to pick them up from school even on the days I work. My husband works at least 4 days a week and typicaly gets home just before or after bedtime (although he does take them to school on the mornings I work). I am self-employed and would have the ability to change my work days to accomodate the children's morning schedule. As I have been, and continue to be, their primary care-giver would I likely be awarded joint custody but with the kids the majority of the time (ie my husband would get them everyoher weekend and a one day a week?) or would the judge be likely to decide on shared custody (one week with me and one week wih their father)? The probable outcome would have a huge impact on whether or not I pursue the divorce.