frequent UTIs

Aubrey
Help please! 
I'm just getting my second UTI in a month that has started the day following sex. I always clean up after wards and wash with soap and warm water. I always urinate afterwards as well. 
I went to minute clinic for Meds last time (about 3 weeks ago) and they sent my urine for a culture and it came back as E-Coli. (Not sure how since I always wipe front to back)
Yesterday my husband and I had sex, I washed, urinated, and I had not had a bowel movement yesterday. I also had a few drops of blood but I'm also 4 days from AF and 10 DPO. Soooo not sure if the blood was in my urine or if it was from implantation. 
Anyone else have UTIs frequently? 
If so- what can I do to prevent them that I haven't done already? 
Does anyone have a SO that smokes e-cig? Could the chemicals from it that ends up in his saliva be causing the UTI?