Sometimes, we don´t have safe sex, and there are several possible reasons why:

Lack of knowledge about HIV and other sexually transmitted diseases

Sometimes we lack information about HIV and other STDs. This may be because we haven´t learned about taking care of our health properly, or because in some cultures there isn´t a lot of knowledge about condoms or how using them can prevent the transmission of STDs.

its

Being embarrassed or not knowing who to ask

Maybe you have a lot of questions about HIV, or about things you aren´t sure you´re well informed about. Often, you don´t ask anyone these types of questions floating around in your head, because you´re embarrassed or don´t really know very well who to turn to.
Never be ashamed to ask someone, this is a sign you´re taking care of your health and that is the most valuable thing you have. It´s good to talk about these things, this way you can find out things about HIV and other STDs that you didn´t know before, or had mistaken ideas about.
You should see your doctor and ask about anything you need to. He/she is there just for that, to help you in any way. There are also many organizations and information hotlines about health related issues.

telefono

"It can´t happen to me!"

There are people out there that believe HIV is only for drug addicts or that HIV only exists in third world countries; or even that it is just something that happens to others and it could never happen to them.

Well, realize that that´s exactly what those other people thought before they got infected/re-infected with HIV. AIDS doesn´t discriminate. There aren´t high-risk groups, although prostitutes and homosexuals have been mistakenly targeted as high-risk groups. What is true though is that there are sexual practices that are at a higher risk for HIV transmission.

Drugs and alcohol

Drug and alcohol use can make us lose control of what we´re doing and can facilitate having unsafe sex.

Sometimes you don´t want to use condoms

Sometimes, you may not feel like using a condom, and you may offer a sex worker more money for a service without a condom. Don´t misuse your health, it´s something more valuable than money. Even though sex without a condom may seem better right now, in the future it could mean living your life with an incurable sickness.

Tell him that you have his best interests in mind, and that you don´t want to have risky sex that could be dangerous. Try to explain the importance of condom use.