Uhhh no, Peter is and will always be entirely to blame for that situation. Madi told him before Fantasy Suites, there likely wasn't a good time to bring up "Oh BTW I'm a virgin" in their few dates before that. And it's possible she was fine with Peter sleeping with other women until she developed real feelings for him and he outright told her "I love you".

Peter should have grown a pair and told her beforehand that sex was important to him and that he was planning on having sex with the other two. Madi let him know about something that would hurt her, Peter acted confused and did it anyway, then tried to romance his way out of the consequences.