My home button on my IPhone 4S isn't working?

Well it's been fine up until today when it stopped working. I don't understand how other than it might have overheated? I try not to let it die (it normally doesn't), I rarely drop it, I don't press down too hard on the home button and it's never around water other than the odd time when I've sweated and it's got onto my phone but it's never gotten near the home button(inside pockets in my jodhpurs.). I never let it near my horse either, it's always in safe hands. My mum says its my fault. Is it? And how can I repair it? I have assistive touch on now but it's quite annoying.

If it has quit working and you have had to resort to using assistive touch, the only people that can fix it is the Apple Store and hope the phone is still under warranty. If you don't want to do that or you are not covered under a warranty, you can take the risk of taking it to a 3rd party electronics shop and see if they can fix it. From what you have said, it sounds like it has been in really good hands. You may have just gotten a bad home button. It does not sound like it was your fault