I think you need to do a lot of research on bipolar disorder and mental health in general.

I have PTSD and if I told someone that I needed to be alone right now, I'd take HUGE offense if their attitude was that this wasn't a specific legitimate reason for breaking up. Yes, it IS a very specific and a very legitimate reason for breaking up. Sometimes when dealing with mental health issues, we do indeed need to be alone. He may be at a breaking point and just need some distance right now. (A huge part of symptom management is knowing when we need what, and sometimes that "what" is simply space.)

I don't think he's trying to take your love for granted. You need to remember that being in a relationship with someone who has a mental disorder requires (yes, requires) you to give a little more in terms of understanding their struggles and making allowances for when symptoms emerge. No, I'm not saying that you should tolerate disrespectful or abusive behavior, but if you think this is going to be like a relationship with someone who doesn't have a mental disorder....you're wrong.

It sounds like you really do want to be with him, so please do a LOT of reading on bipolar disorder. Is he type I or type II? They manifest themselves differently. Is he medication compliant? I know not everyone with bipolar disorder takes medication, but it is one of those disorders that can indeed be managed more effectively with prescription drugs.