Condoms Don’t Work
If used consistently (in other words, every time one engages in sex) and correctly (see below) condoms are highly effective in preventing HIV/AIDS.
Human error introduces the risk of transmission—for example, if one does not use a condom all the time or uses the same condom more than once.
Condoms only break as a result of incorrect usage, if for example, not enough of the correct lubricant is used or if it has not been stored correctly or is past its expiry date.
Latex condoms provide a continuous barrier to micro-organisms, including HIV, so it is untrue that condoms have “holes” in them which allow HIV to pass through.
Source: The Body: Basic Facts About Condoms and Their Use(also includes tips on how to use a condom correctly).
Additional Source: Terrence Higgins Trust(includes step-to-step guides for using condoms as well as femidoms and a “troubleshooting section” for what to do when it is used incorrectly).