How long can sperm last in a household freezer?

My partner had a vasectomy 3 years ago. We really want another baby but don't want to have a reversal. We have been using sterile needles directly into his testicles to withdraw semen. It's quite painful for him and unless he's drunk we can't get much out. If I get a whole lot out at once, can I freeze some of it in our freezer? It's quite new and never makes my frozen veges mushy? Has anyone else tried this and been sucessful? Or do i need to extract semen while i'm ovulating and use it fresh?