My husband invited his son from other woman to attend yesha's 1st birthday . How can I break the ice ?

I have friends who have partners with a child/children with another woman, and they're cool with it. Try to act as normal as possible to avoid tension. You may invite the kid to join activities with your child and other kids in the party so one will be left out. Yes, I agree with Rollie, let all the kids enjoy the company of each other in this one special event.