is he undiagnosed bipolar?

Please help i need advice do you think that my partner is bipolar?
Please we have been together for four years living together for three years and we were due to get married at the end of this year had a wonderful relationship apart from his severe depression. He ended our relationship three months ago completely out of the blue said he was a complete mess didnt know why he wasnt happy. He has never been able to sustain a long term relationship, he courts danger does reckless things with money cancels bills cant handle any responsibility is in a massive amount of debt. He goes off on spending sprees and spends money he doesnt have. I have seen him be manic he gets very excitable and then becomes severely depressed. He says its like he has 100 voices saying to him how useless and worthless he is and then they all punch him in the stomach! sometimes he wishes he was dead. He is delusional its like he lives in a world of unreality one minute he wants to buy a boat so we can go and have cups of teas on it at lunchtime he wants to buy houses we cant afford wants to be a pilot in Monte Carlo and then gets severely depressed when these things dont happen!. I am at my wits end with it all so emotionally drained. When he finished the relationship he was so horrible cold - like a different person really nasty and vindictive and he has shown himself to be a liar. He left me for five days didnt contact me said he didnt know what was wrong with him then he came back and ended it saying he doesnt want to get married this isnt him !! then he said he doesnt want any responsibility in life doesnt want a morgage etc ! Awful! when I met him he was on meds for depression but he stopped taking it said it didnt do anything. He moved himself into an apartment carried on with his life like our life never existed! What has happened to the sweet kind person I thought I knew! Now he is back in touch texting me all the time telling me he misses me thinks about me everyday that he isnt happy now. Is he cycling? Ive read bipolars follow a cycle. He is having breakdowns at work - he has never been able to hold down a job longterm or not for long he is now having CBT treatment - Hypnotherapy with a therapist. He says he is a complete mess. I love him with all my heart but it will help me enormously if i understand that he behaves this way because he is bipolar . All his family have mental health problems - severe depression and none of them can have relationships longterm. He is also extremely introverted doesnt like to socialise with people his family especially his mother are all the same his brother has aspergers. My life has been completely turned upside down will my life always be like this with him. It has been hell so far and my heart is broken in two. Also he becomes manic and goes skydiving every weekend - he has become obsessed with this. Please can you reply to me as soon as possible thanks