It does depend a lot on who you're computer programming for and a bit on what kind of programming you're doing.
If you are working on a big bureaucratic system with projects, deadlines and testing - you're bound to be expected to work weekends when it gets behind and you may be expected to hang round on weekends for testing and pilot runs. A favourite time for implementing code is on the weekend when it can cause fewer problems in the office.
Invariably when a big project gets implemented - stuff goes wrong, and programmers are expected to be on hand to fix it immediately - not that this is good strategy because these kind of immediate fixes often make things worse - but this could mean you're working all night and all weekend from time to time.
If you want to write games software, you may end up with no life outside programming at all. However if there are people with the same devout commitments as you - like the footy team itself - and you get to program for them, it may be more flexible and able to accomodate your needs for a life outside programming.
I reckon - you might make 80% of your commitments but not all of them. If this is a problem, get a job that requires no after hours work. Like a receptionist maybe?