Am I going to be the evil stepmother?

Two days ago, my husband, Peter, and I got the results of a paternity test online.

Now, rewind. 2 years ago when I was about to get married, I sat on the couch with my husband in my 1 bedroom apartment. We were talking about children.

He informed me that there was this girl, Clair. My husband had been friends and only friends with Clair for a while, they worked together at a video store, they partied with the same people, ect. Her boyfriend of 2 years dumped her. She, Peter, and their mutual group of friends partied, got completely shit-faced and had relations. Peter doesn't actually remember the sex. He remembers drinking then waking up butt-ass naked next to Clair. They didn't talk after that. She finds out she is pregnant 5 months later. She tells Peter that she is "having a baby, it's name is going to be Lily and you are the father." After he sits down to actually think about what to do, he informs her that he wants to be involved and wants to go to the doctor with her and wants to love and raise this child, well in guy speak, but you get the point. They set up a doctors appointment and she is supposed to give him the time. She informs him that she wants a relationship. If they are going to play house they may as well give it a shot right? He wasn't into her. He told Clair that he wants to be a part of this child's life, but doesn't want a relationship. She stopped talking to him after that. He tried calling, texting, ect. He finally gets a hold of her and she tells him that the baby is not his.

I was informed of all this a week before my wedding. I was ok with it. I thought, well I have dated a guy with a kid before and it was fine, so even if this kid shows up in 10 years, it will be great. whatever.

My husband and are got married because we loved each other dearly. We got married when we did because I was four months pregnant. Now 2 months ago, my dear mother in law sees Clair's mom about in town with Lily and Lily happens to look an awful lot like Peter, so she informed Peter about this. She also told him she was going to write a letter to Clair inquiring about Lily. He said ok. Clair responds and says yes it is Peter's. MIL has been babysitting this child since then. Clair's babysitter conveniently quit when my MIL offered to babysit free of charge, a child that has not been proven belongs to my husband. I found out about this a month ago.

My husband informs me of all this, after keeping it to himself for a month, 30 minutes before we were leaving for his grandfather's funeral.
He had not yet spoken to Clair. He called her, they did lunch, and him and I and Conner, my 11 month old, met this 2 year old little girl. A couple weeks later, Clair called my husband saying she had a party to go to and wanted to know if he wanted to watch her overnight. We did the paternity test then and they overnight visit went well. We mailed off the package and 2 days ago got the results.
I am now a stepmom. I was just getting used to the idea of being mom. Now keep in mind I have always wanted to be a mother and have some issues with my fertility. So when Peter knocked me up, I was happy. Not the best timing, but happy nonetheless. Lily is coming next weekend to stay with us.

to be continued...

*all names have been changed to protect those involved, but mostly to be able to write whatever the hell I want*