You shouldn't feel bad.. In my opinion you did all you could to try to prevent it. Your boyfriend was comfortable enough not to use protection after knowing the risk, so truthfully thats on him- don't beat yourself up. GHSV1 hasn't brought many issues to my relationship, in a way I feel it's making it stronger. Just make sure neither of you are angry, don't be spiteful trying to throw it in each others face and forgive. That includes forgiving yourself.