Whether we have several partners all at once or one after the other, the risks increase the more people we have sex with.
The risk of sexually transmitted infections is much, much higher when people have sex in groups. The chances are that someone in the group will forget to practise safer sex or that a condom or other barrier protection will fail – especially if alcohol or drugs are involved.
Sex with more than one person at once is unlikely ever to be risk-free, but if you are thinking about having group sex, read our page on the risks of group sex.
If you choose to have more than one regular sexual partner, everyone needs to take extra care.
If one person in your network of sexual partners gets an infection, everyone else could catch it very quickly. There's also a greater risk of emotional upset – especially if some people are not being honest about the fact that they are having multiple partners.
Can you say for certain that every person you've ever had sex with was free from sexually transmitted infections at the time? Can you say for certain that your current partner has never slept with someone who had a sexually transmitted infection?
It's unlikely anyone can say that for sure.