I can relate to how you're feeling. My AH and I have been separated for 6 weeks now. I've been holding a ton of resentment because I picture him enjoying his time living as a bachelor with no responsibilities while I'm still here taking care of our daughter, the dogs, the house, etc.
I talked to my therapist about it and she asked me if I knew for a fact that he was enjoying living on his own. I told her that no, I didn't know for a FACT, but that I'm sure he was living it up over there with no one to answer to. Again, she asked me if I KNEW that he was having fun. I had to finally admit that no, I didn't know that, it was just the image I had built up in my mind.
In reality, AH just recently admitted to me that he's in a deep depression and spends almost every night crying in front of the tv. Whether that's true or not, I have no way of knowing. But it's vastly different than the version I had formed in my head, of him having a grand old time without us while I tried to pick up the pieces of our lives. Either way, I have to keep the focus on me, but it helped to realize that the scenarios I create in my mind don't always match the reality.
Sorry you're going through this right now, I know how bad it hurts.