confused

Ok ladies I need some advice too… I am 31 y/o already a mother of one who is 11 y/o. It really hasnt been confirmed by blood, but I took a HPT yesterday and it came back positive. At first I cried, cause my child is almost a pre-teen and I was sure I wasnt having anymore by now. The father of this one on the other hand, thats where the situation gets sticky. Fist of all he is younger than me, and already has a soon-to-be 2 y/o. I also forgot to tell you that we work together and are the best of friends. We have been seeing each other for about 3 years now, some people at our job knows,others speculate. My problem is I dont really want to tell him that it’s his, cause I know how upset he was about his other child being born, of course until she got here and know she a little daddy’s girl. But he was devestated at first about it and I was there to help him through the pregnancy with his first child. I know he has a right to know that this is his baby, but I am scared that our friendship will be over. I truly do love this man I feel like he his my soulmate, but now that I am pregnant I just dont know what I feel anymore. Luckily this week he is on vacation from work, but next week what will I do?, I have no idea how I am going to tell him this.