Sorry to hear that about the burning sensation that you are feeling. One of the most likely reason behind your problem is UTI or commonly known as urinary tract infection. In this infection, a person who is affected by it feels burning sensation during urination. There are other symptoms also like feeling feverish, frequent urination, troubled abdomen. Hence, urinary tract infection might be the reason for this problem. However, you also told that there is flow of blood and also your boyfriend cheated on you. For this, you can get yourself tested for sexually transmitted disease as the nearest hospital. If you are suffering from vaginal discharge or irritation also then it might be a case of sexually transmitted disease. You should get yourself tested as soon as possible. Herpes or commonly kwon as genital herpes is a disease which is sexually transmitted from one person to another during intercourse whether anal, oral or vaginal. This disease as evident from the pics of herpes is very dangerous. Those people who suffer from such diseases develop ulcer on their genital parts. It is not necessary that only women or men will suffer from them. Both men and women can suffer from this disease. There is no proper cure available of this disease. In most of the western countries the number of people infected by this disease is in millions. People are helped by medication which reduces the effects somewhat. Hence, protection during sex is very important. Take care.