Don't be so quick to run. Maybe he's just ashamed to be bisexual and didn't know how to tell you.

Try talking to him compassionately, acknowledge you could never give him what a man does, and decide if you can make room for that in your life. Many people do.

Or throw away the relationship and start looking again for someone to start over from scratch with.

The dishonesty is bad, but understandable. Lead with love and see what happens.