I Changed My Mate on Mating Ceremony

"I was the pack's chief healer and my mate was just an ordinary warrior. Everyone thought we were not a good match, but I didn't mind. I accepted his proposal without hesitation.But on my mating ceremony, my mate's ex-girlfriend Serena suddenly came in with a little boy. The little boy hugged Marcus' legs and called him daddy.I thought it was some kind of scam. But when Marcus saw the child's mother, his face went pale. Then he showed an expression I'd never seen before—pure adoration—as he scooped the boy into his arms."Let's cancel our mating ceremony. I need to mark Serena first and raise the child with her. Don't worry. Even though I'm marking Serena, my heart belongs to you."He thought I loved him so much that I chose to be his second mate. He didn't expect that I would just calmly contact my childhood friend Alpha Dominic. "My mating ceremony is all set up, but I'm missing a male lead. Would you be willing to come mark me?""