Bacterial infections are usually treatable with antibiotics (gonorrhea, syphilis, chlamydia). Viral infections (Herpes, HPV, HIV, Hepatitis B and C) are often not curable but symptoms can be managed.
Anyone who is sexually active at least once can get or give an STD
Condoms can help to prevent some STD's but are not 100% effective even with consistent users.
The most common STD are present in up to 30% of the sexually active population without symptoms