So here is the difference: Child support is for the children of the marriage; spousal support is for a former spouse.
In both cases, there is a formula under Colorado law. The formula for child support is found at Colorado Revised Statutes § 14-10-115. The formula for maintenance is found at Colorado Revised Statutes § 14-10-114.
If someone is obligated to pay both child support and maintenance, we advise that it is best to write two separate checks, and indicate either “child support” or “spousal maintenance,” as is appropriate, on the checks. If someone is down to her or his last check and can only write one check, the payor (person making the payment) should write a notation on the check of how much is for child support and how much is for spousal maintenance.
Generally, child support ends when the child for whom it is designated reaches the age of 19 or becomes emancipated, whichever comes first. If, however, the child is handicapped prior to the age of 19 years, it may be extended beyond the age of 19.
Maintenance often is ordered (or agreed to) for a set period of time. Often, that period is about one-half of the length of the marriage. For longer marriages, however, or when the spouse is handicapped and cannot support himself or herself, it may be open ended, which means it does not have an ending date.
In general, it is a good practice for someone receiving either child support or maintenance to keep track of how he or she spends the money. It is highly unlikely, however, that a recipient will be required to account for how he or she spends the money.