Good for you! Cosleeping is great! Some babies need that closeness with mom and who can blame them after being inside us for9 months?! There is a transitional period while they adjust to being on the outide from about 3-12 mos. While you might be missing a part of you (when he was inside), he's missing you too!
Read "The Baby Book" by Dr. William Sears and you'll never feel bad about cosleeping again! The author is a seasoned pediatrician who raised 8 kids with his RN wife and they have written over 20 books about child care. Now 2 or 3 of his kids are Drs in his family practice as well. They've been on Dr Phil. This is sort of a good starter book if you have not read any of the others, it's got a lot of info from the other books (see also Pregnancy Book, Sleep Book, Breastfeeding Book, Nutrition Book, Discipline Book, Preemie Book, Fussy Baby Book, and more! this is just off the top of my head!) and "The Baby Book" covers birth to age 2.
For a nursing baby, the benefits are great. They cry less since you are right there and can nurse immediately, which is also great for moms as you get more sleep. Frequent crying wastes energy they should be using to grow and learn. They will learn security and love from the beginning. Patience can be taught later. Yes, it reglates their breathing as they hear and feel mom or dad breathing. Great for preemies or those with sleep apnea issues. Cosleeping babies do not die of SIDS, that's why it's called Crib Death, it happens in a crib when babies are sleeping alone.
On a personal note, we are still cosleeping with our son who is almost 3, and on a waterbed (never had any issues) which I like because he cannot fall off, it has rails around all sides. I found out that most of our friends were cosleeping as well and tend to gently transition their kids to their own beds/rooms once breasfeeding was over, usually between 12 and 24 mos, some longer. Most of us let our child wean on his or her own. Our son does sometimes sleep in his own bed that is in our room, but prefers to sleep with us! I know one day he won't want to have anything to do with us so I don't mind sharing our bed for a little while... although Daddy is starting to nudge!