Somehow cutting yourself some slack from the eating and/or exercise plan followed during the week has become acceptable weekend behavior. It doesn't have to be this way.
When you build a plan around your preferences, ability and schedule; there isn't a need to "reward yourself for being good all week". You're never good or bad on this type of plan, just doing your thing.
That might be having a burger & fries with your son after basketball practice, or skipping a morning run because you worked late the night before. Your schedule is always going to be changing. You'll never be able to build your life around a fitness program for very long - it has to be the other way around.
So if your weekend plans involve going "off plan". It's time to evaluate the plan you've been following.
Have a great weekend!