There are many threads on this site on threesomes. Search and you will find the pros/cons of your interest. I know in the past, Evil has posted a great deal on how to find another person who may be interested. Read around and find some of your answers, there are many threads!
Here is one:
http://www.sexinfo101.com/forum/marr...ght=threesomes
Do a search on this site on "threesomes"...
Threesome - Question for you!