Dealing with an ex

My issues is every week my fiancee has to drop off his child support check to his ex personally ( This is his choice). This is something he does once a week. I've asked him to put the check in the mail, but for some reason he needs to leave it at her door. Weather she is home or not. We don't live far from each other, I've asked him why can't he just mail the check. She waits a week before she deposit the check anyways. So why drive out to her place instead of mailing it? Am I making a big deal over nothing?