Found out bf has a child

The day before father's day my boyfriend found out he has a 7 month old. We knew it was a possibility but now that we know for sure I've been in this depression state. Me and him have been together for a year. I really don't know how to handle it. I don't even want to be around him, he started liking pictures on the girls Facebook, and now they are gonna have communication all the time... I have a 1 year old but I have nothing to do with her father. The mother of his child I've known for years. Anyone else been through this and ways to overcome this depression??