Four separate relationships for one person seems like maybe a little too much to me. Even if he can juggle it, you wouldn't get much of his time/energy. Do you think you would be cool with that or do you think you'd end up feeling like this: http://www.polyamory.com/forum/showthread.php?t=19512
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.