Sleeping with boss ecstacy!?

My boss is 39, a married man with 2 beautiful kids. We have been sleeping together for almost 2months. im only 19 but im 100% sure i love him. One of my co-workers found out about us a fortnight ago [catching us at it in his office after work] and she's good friends with my boss's wife . recently i found out im pregnant with my boss. i really do not know what to do. im so scared and i know its dumb posting this on here but there's no one else i can talk to. if i tell my boss he'll flip as he is enough trouble after knowing my co-owner knows about our fling.i cant bring myself telling my family or i know they'll chuck me out. help