I had to give up bubble baths for awhile as I was also having UTI/ yeast infections. Not due to Crohn's but do to being on hormonal BC.
I just used bath oils - very lightly or no products at all. Sometimes epsom salts or homemade epsom salts ( drops of your fav perfume mixed into a cup of epsom salts then placed in a jar and used 1/4 cup every bath). I often showered and washed everything off when getting out of the tub and that helped.
I also did the following - cotton underwear ONLY, no undies on while sleeping, drank Cranberry juice daily, took garlic piils, NO pantyhose everyday(occaisionally on ok) cut down on sweets in my diet, go get up and pee very soon after intercourse( I still do that cause if I forget I will still get a UTI from time to time)
Hope that info helps