To answer your question: Fleshlights are great for providing a more "real" sensation, but I (Or my partner) would recommend trying tenga Flip holes for more intense sensation. The materials look a bit scary in the pictures, but it is actually quite soft, jelly like and he rates the Flip Hole (He has the Silver) as being very high up his list for sensation. A cheaper version, that he also rates highly for sensation, is the £12.99 lovehoney Double Stroker (The black one) again it looks scary but feels great for a tighter, more textured experience.
As a fellow UTI sufferer (I had to have my urethra stretched due to constant infections) I can feel her pain. It really is extremely uncomfortable. If she is ever willing to try sex again, i can give you some tips that really help the most. She may know most of this, but this may help others too:
1) Wipe from front to back, always, from vagina back to bum, never back to front, as you are potentially pulling bacteria towards the vagina Like 80% of UTI are caused by e-coli bacteria that lives in the intestines/bowels naturally, but once it gets into the urethra...disaster. It is said that a womans risk of being a recurring UTI sufferer can have a lot to do with the distance between her urethra and back passage. the shorter this distance, the more chance of bacteria migrating.
2) Get rid of the thongs and g-strings and go for pants. Same reason as above, the material between the buttocks moving about can help transfer bacteria
3) I was once told that drinking cranberry juice helps, then I was also told that cranberry juice is a double edged sword. The bacteria that causes infection feeds on sugar and grows. Reducing sugar intake will help, and cranberries have an enzyme (or something) that helps stick to the bacteria and flush it out......but normal cranberry juice is also packed with sugar, which also feeds the bacteria...go figure! So...get the sugar free version (Which tastes urghh) or get cranberry vitamin tablets instead. I also recommend looking into a substance called D-mannose. People rave about this stuff for UTI infections.
4) This one is like, the MOST imprtant one, for me this one is the biggie....pee after sex. As soon as sex is finished, go pee, to help flush out any bacteria just making their way into the urethra. Even if it is only a dribble...still pee! This one helped me massively.
5) Shower rather than bath. I hear bathing can introduce bacteria into the urethra easier whereas showering washes any bacteria downwards and away. Also, shower the vaginal/anus area before and after sex (Flushing away the risk)
6) Drink more water during the day. This one is kinda obvious, it keeps you peeing regular, therefore flushing out your system more regularily. Not drinking, and therefore not peeing for hours and hours, gives any bacteria already making its way into the bladder, time to multiply and take hold. Flushing it out regular is helpful.
Okay enough about UTI, and onto the Lubricant thing. here is a tip i learned from Yes...Get a bottle of their oil based lubricant (Yes is the only oil based lube I know that is safe for vaginal use, others not so much) apply the oil based lubricant generously. Then get a good, paraben, glycerine, natural as possible bottle of water based lubricant and use that over the top of the oil based lubricant. This method is supposed to be great for ladies who suffer vaginal dryness or sensitivity. Its a double layer of slip. The oil lasts long and provides the main layer, followed by water based to add a real slickness on top.
Good luck. I hope things work out for you both.
PS: Condoms won't help much in stopping UTI. Unfortunately it is often caused by bacteria being transferred from a womans back passage area to the front, and even if the penis is encased in a condom, it still moves back and forth around this area and can still transfer bacteria. I guess it is the one infection condoms cannot stop. Even fingers and tongues can transfer the bacteria :(