‘Can an ex ask for a retroactive increase in child support from 1996 to the present? She was paid child support weekly for all this time and now wants more money to pay for college and apparently this is her solution. Since she had the chance to increase the support all these years, can she do that?’
Whether she can ask for retroactive support really depends entirely on what you mean by “retroactive” and the facts of your situation. A request for support or an increase or decrease in support can be made effective to the date of the initial filing of the request or action for support. For example, if she filed a request for support or for a change in support back in 1996, but it was never decided and entered, and then a court calculates and enters support this month, then yes, they can make it retroactive to the date of the original request. This is true even if you have been paying support all along, but not under a court-entered support order. In fact, it’s true even if she agreed out of court to a different amount or even to having no child support (because technically the only child support a court will recognize is that child support which is paid under a court order).
However, if no such action was ever filed – if right now this is the first time she is filing anything about support with the court (and if no other agency, such as the DA’s office, has filed something to effect child support in your case), then in most states she would not be able to get that retroactive support.