Congratulations!!! I love his name, and I named my Jake after our baseball field, which was "Jacobs Field" until this year when they changed it to "Progressive Field".
When I brought my second male (Jackson) home, Jake was very jealous at first. He was curious about Jackson, but he really wouldn't play with him. Jake got very mad at me, wouldn't let me hold him for the first couple days....made me so sad. But, I just kept making sure I paid lots of attention to him as well as Jackson. It took about a week for Jake to "accept" Jackson, and now they are buddies and play together ALL the time. Of course, they always find one toy to bicker over lol.
I think the main thing right now is to let them get used to each other gradually, on their own terms. I watched my two very closely at first to make sure there was no fighting or aggressive behavior. Jackson is the bigger of the two at 6 1/2 lbs. Jake is 4 1/2 lbs. It almost seems as if Jackson realizes that Jake is smaller and he has to be more careful with him. They do get into some rough playing, but I usually try to stand back and let them do what they do.....of course, I would step in if anything got out of hand. Just make sure you pay the same amount of attention to all of them. Before you know it, they will all be best of friends and have fun together. My boys are inseparable now.
Try to nip any aggressive behavior in the bud. I think in the beginning, Jackson thought he could be the "alpha" around here. He would kind of push through Jake to get toys or to get attention. I stopped that behavior in the beginning and let him know that it's ME that is the "alpha". Once they learn that, everything goes so much smoother.
Can't wait to see pics of your new baby! CONGRATS!!!!!