I had a period of frequent UTIs at one point in my life. When I ended my relationship with my partner, they went away. I only had UTIs while I was with this guy and never before and after. I heard later that this is not uncommon, that sometimes the "flora" of two people are just not compatible. I don't know if there is anything that can be done with that, or just to grit your teeth and bear it, or could there be something the partner could do? Have the partner drink cranberry juice also? I don't know, that is probably a silly idea, but if there is something the partner can do to tame their own flora, I would be very interested to hear.