Should I have kept my mouth shut?

okay, well my shitty ex boyfriend cheated on me with two girls while we were on a "break". Come to find out he didn't use a condom with either one of them. He doesnt even remember the first girls name! Well the second girl he had with went to my high school so we aren't friends, but more like aquantinces. She called me to apologize for what she had done and that she didn't realize my boyfriend and I were so serious. [we had been dating for almost 2 years] She doesnt have too many friends and it seemed very unlike her to get drunk and let someone take advantage of her. For whatever reason she felt she could trust me and called me quite a few times over a couple weeks just to "talk." She said she had been sick since the incident and I suggested that she go get checked. She was in shock when I told her that. She was under the impression I was his only ual partner until her. I explained that he had unprotected just a week prior to having with her. [cont'd]