Historically, if contributions were roughly equal, then there was a tendency to start from a 50/50 basis and to adjust this to allow more to a spouse who would be out of the workforce due to childcare responsibilities, or whose earning power was much less, resulting in distributions such as 60/40 or 55/45. However, where child support is to be paid, this approach may no longer be applicable as the child support may itself adjust for the extra expense of caring for children.
Deviations might occur where one party had made a significant separate contribution, such as using compensation monies or an inheritance to reduce the mortgage or purchase an investment property.
People should always get advice from a lawyer who is experienced in family property law.