On and Off Again Troubles w/ ADHD BF

I've been in a relationship with someone with ADHD for a little over a year now, and all I can say is that I'm tired. We've broken up and gotten back together 4 times now. It's a cycle: he gets sick of the routine we're in, he wants to break free, so he breaks up with me. Then, he misses me, and comes running back. And I take him back every time because I love him so so much, and when we're together, it's the most magical feeling ever because he's so focused on us. But I can't help thinking, will we last? Does any one else have this syndrome in their relationship and have you gotten past it? I need some hope. He's my soulmate.