Who am I?

What to say? What to do...I'm so lost. I vacillate between staying and thinking things could be ok and being certain I can't live like this the rest of my life and wanting a divorce on a daily basis.
A random unrelated experience...at the counselors office, we had separate appointments that day and I was waiting for H to finish in the waiting room with the baby. Glance over and there's a woman staring at me who closely matches his description of OW even down to a poem tattoo on her forearm that I saw in a topless picture of her discovered in a secret email account. I've never seen her face unfortunately. Same long dark wavy hair, very tan and kind of weathered looking, older, and if she went for therapy (they work for the same company), that is where the company sends its employees for it. She seemed maybe a little bit larger than the woman in the picture but I became convinced it was her. I was shaking...so anxious and filled with rage. To hide my shaking I started bouncing the baby on my knee. When he finally showed up she looked at him for a minute and smiled then looked out the window...waiting room courtesy, or jokes on me? I asked him if it was her and he said it definitely wasn't and explained how that woman differed from OW. This has also happened at the beach. Basically this happens everywhere...he claims to not be able to remember her last name even though he was with her for over a year. I feel like I need to see what this woman looks like. I don't know why. I guess to see if I'm prettier than her? Maybe by seeing her I'll be able to understand what she has that I don't? What is so wrong with me...I know she's thinner than I am, that was obvious in the picture. Also much smaller chest than mine...that's how I console myself when I think of her being really thin.
I hate this woman so much...I hate him for doing this but I want her to die. I can't help it. Apparently she liked him to choke her when they would have sex, which no offense but I think is fucked up. I fantasize about choking her to death and screaming in her face asking if she likes it now... that.is.messed. I am such a non-violent person...but obviously, deep down I'm still a cave woman. I know that I would never actually do that but even for that thought to enter my mind is insane. Every time I hear about a car accident I hope it's her. I'm not exaggerating when I say I hope she dies.
I feel so insecure it's pathetic. I can't stop wondering...am I attractive? What do I look like to other people? Deep down I feel like for a mom of 2 I'm not too bad, even if I could lose some weight it's nothing major. I'm still well proportioned & have good curves, have a nice face, still take care of myself appearance wise, I'm friendly, I'm not a bad person...I'm trying to convince myself. He says she's not as attractive as me but obviously he'd say that. He claims it was just the thrill and danger of it. Then why didn't he want to break it off with her when I found out? He asked if it would make a difference in my leaving him if he did tell her it was over. Asshole.
I recently got my hair done and highlighted. It's been dark for a very long time and I needed a change now. Needed something good. I wonder if I'll ever really feel good again...and how I'll know if I should divorce or not. Being in limbo sucks.