Try treating the uti/bladder infection as a systemic problem, because your body is a whole system. You may need to adjust your diet by staying away from high sugar and simple carb foods. Hydrate with plain water regularly so you are peeing frequently throughout the day, at least every 2 hours, which will help flush out the bacteria and keep them from adhering to your urinary tract.

Cranberry juice (pure and UNSWEETENED not Ocean Spray or 'juice cocktail') or whole fruit supplement pills are known to be helpful because they acidify the urine, killing bacteria and also have a compound that is thought to keep the bacteria from adhering and creating a bio-film (which is a strong colony) along your urinary tract.

What is likely happening to you are flare ups of uti causing bacteria; you are never really getting rid of the colony, they just get beat down by any treatments you take, like antibiotics, and then when you stop taking that medication they come back. We know that using antibiotics long term or repeatedly for the same infection is not a solution, since they will just cause a major imbalance in your body's flora, killing broad spectrum, and as soon as the pills are out, certain bacteria multiply and fill the void causing a reinfection.

If you look at cystitis as a systemic problem you are more likely to find a lasting solution. Prevention is key, so insisting that any sexual partners wash their parts, hands, trim and scrub nails, wash their face, even brush their teeth, will keep the bacteria load on your body down. Of course, peeing after any sex is paramount.
Coconut oil, while not compatible with latex condoms, is a mild antiseptic and excellent lube. Boric acid (in Borax laundry powder) is also used for yeast infections, candida, thrush, ect. and some people take it internally in diluted doses to help with infection. There are some interesting articles http://www.health-science-spirit.com/borax.htm and http://educate-yourself.org/cn/boraxconspiracy03jul12.shtml

You can also try washing the cup with soap and hot water every time you remove it and more than every 12 hours and washing your vulva before removing the cup as you may be introducing some extra bacteria. Even though your hands are washed, there is always bacteria on your labia and everywhere.

Hope this helps, and good luck!

Gah, me too.
I'm only on cycle 2 so I'm really not quite qualified to comment on consistent infection.
I wash my cup every time I change it (just with hand soap) but a couple of times I had to empty in a public toilet (super heavy flow) & there was no soap in the disabled toilet so I could only rinse it.
My Dr has directed me to a over the counter supplement.
Basically uses the flesh of cranberry to create a teflon like effect on your urethra so the bacteria can't stick. Hopefully it works.
I'm assuming it's my method of insertion. I do tend to run the cup along the whole area to slip it into my vagina. I can't seem to do it any other way.