Hi. My g/f has CPTSD and we've been together three years. I haven't done what you did but I check out other women all the time, then feel terrible for it. But please don't blame yourself. My theory is that you're looking for comfort and safety, when your g/f isn't providing you with any. She needs you to provide her safety, so can't see your own need for safety. I love my partner and I have grown with her. Thankfully we have engaged in couples counselling which has given us many tools to help each other, but the trauma's still there and isn't going away soon. I wish I had the answers, but don't beat yourself up about this one. PTSD sufferers are good at making their partners feel like shit, like they've done something unforgivable. Remember that you need love and care and safety too and it's not wrong to look for it (even if you don't in the end do it).