I keep giving girls Bladder Infections

I had unprotected sex with my girlfriend a year ago for the first time.  Soon after, like 2 days, she got her first bladder infection.  It seemed as though every time I would *** inside of her she would have pain shortly after, or she would get a new UTI or bladder infection.

We recently broke up.  And now I am seeing a new girl.  Two weeks ago I had sex with her for the first time.  I didn't *** inside of her, but I didn't wear a condom the whole time.  Two weeks later, she tells me she is going to urgent care because she has a bladder infection.  She has never had one before.  

Could it be me who is causing these bladder infections?  Is there something wrong with me?  What could it possibly be?