J.B.
I'm a mother, but not a mother in this situation. However, I STRONGLY urge you to contact PFLAG (Parents and Friends of Lesbians and Gays). They have an entire division devoted to adolescents, coming out, parents dealing with that, etc. It sounds like you are doing all the right things and are supportive. I'm so happy you told him you love him no matter what. That's SO important for him to know. Of course depending on how he deals with it in his life at this age, he could be in for some rough times at school. It will all depend on where he goes to school. That's where PFLAG might REALLY be of help.
I used to teach at an all-Black high school, and I was shocked to find (and still to know)that the HIGHEST suicide rate, period, is among teenage black males, and even higher in the sub-group of gay/bi black males. I'm not saying that to scare you or suggest that your son is suicidal or anything, but just to make sure you realize that the next few years are going to really be serious for him -especially if he totally comes out as bisexual or gay. Like I said, I'm so happy that you're being supportive -that will help him so much! Just keep those communication lines open, and keep him in therapy as long as he wants and as long as the therapist feels it's warranted.
http://community.pflag.org/Page.aspx?pid=194&srcid=-2