If my girlfriend has a bladder infection and UTI and we havent had sex in over 3 months. Does this?

The man doesnt need to be infected with anything for this to happen-voiding (peeing) right after sex can help flush this bacteria out of the urinary tract so a woman should urinate right after having sex.
Sometimes bladder infections occur because bacteria is introduced into the bladder by other means. When a woman holds her urine for too long before going to the bathroom to relieve herself, for instance. Tight clothing, like jeans, can irritate and lead to UTI. UTI's are very very uncomfortable and the last thing a woman who has one feels like doing is having sex. They are terribly painful-there is extreme burning and your bladder feels full all the time and sex is the last thing one will think about with a UTI so be patient. She should get antibiotics from her Dr and once she finishes them, she will start feeling like her old self again.
You can help keep them from reoccurring by some simple hygiene and common sense. It is best to shower (or at least wash) before sex to reduce bacterial loads in the perineal area. When you have intercourse, stay away from the anal area if you plan on penetrating the vagina. Most UTI's are caused by E. Coli which is found all throughout the digestive tract so the area around the anus is full of E. Coli. Dont drag that bacteria from the anal area to the vaginal area with any part of your body. Sorry, I know this is graphic for some but it is for educational purposes. It really helps, if a woman is prone to UTI's to have hygienic sex. She should always, always urinate immediately after having sex of any kind. Hands are a major source of bacteria so wash your hands before any kind of fore play. If you are aware and are hygienic prior to sex, it will go a long way to prevent reoccurrance in your partner.