Hi, I Got Married 2 Months Ago. We Had Sex

Hi, I got married 2 months ago.
We had sex without precaution and due to which I got a cut/scare on my penis.
Few days after this incident, I was diagnosed with Urinary Tract Infection.
We had sex only once when I was on medication for UTI.
Couple of weeks later, my wife complained about excess itching and burning like sensation at her private part. Gynecologist has advised her to use 'Cansoft cl' which I believe is used to cure infection. My questions:

1. The cut/scare on my penis was due to wrong posture during intercourse or it is common to face such situation after losing virginity?
2. Does UTI has any connection with the cut on penis or with unsafe sex?
3. Does itching at wife's private part is bebecause we had sex when I was under medical treatment for UTI?
4. Will be there any problem in our sexual life because of such incidents?
5. Is safe for me to use Sildenafil?

Sorry for such a long post, bt concern needs your kind attention.