it could be the lubricant, for sure. i seem to have a urethra that is right inside the vagina. really sucks when it comes to UTIs, that's for damn sure. i had a lot of them there for a while, even without using condoms.
do you pee INSTANTLY after sex? i try to pee at least twice within the hour after sex, one of those times being an instantaneous jump up from bed and run to the bathroom almost.
the other thing is that sometimes you can get uti's at the beginning, when you're not used to having sex, and then your body gets used to the antibiotics and keeps getting uti's.
taking some cranberry supplements on a regular basis for a while might help your bladder get back to its normal healthy state, because right now it sounds like it's kind of susceptible to getting bugs.
sorry, i know how much they suck!