Do you use latex condoms treated with a spermicide such as nonoxinol-9?
Was the condom used correctly and consistently?
Are you aware that condom effectiveness can decline due to user failure?
Avoid the use of oil-based lubricants (petroleum jelly, shortening, lotions) that weaken latex?
Sexual contact that involves taking vaginal fluids or semen into the mouth or contact between saliva and the genitals is considered to have some risk for HIV infection, so that kind of contact should be avoid before and after the ejaculation.
You need to watch for correct and clean removal and dispose of used condom.