Who could be the likely father?

Patient: My girlfriend cheated on my on June 20th and July 16th while I was out active duty and now she is 30-32 weeks pregnant she is saying her last period was June 22nd. Her due date was April 12th and according to her the doctor changed the date to march 28th (could be a lie). So to help her I want to figure out who could be the father of the child.Thanks!

Symptoms: Pregnant