Hi, Monique.
Your boyfriend is clearly acting in a controling and manipulative fashion, and a marriage proposal is part of the pattern. Clearly, you are in no position to make a major commitment.
Two things could be happening:
1. This could be part of his personality. Thus, you're not going to change him, which means nothing but misery for you. I'm always amazed how women can rationalize getting into situations where they know they will be abused. Breaking off the relationship may be your best option.
2. He is temporarily not thinking with his brain. Men are notorious for this, and - to a lesser extent - so are women. According to Helen Fisher PhD, an anthropologist at Rutgers, first we are hardwired for sex - part of the procreation biology. Second, we are hardwired to find a mate. A new set of homones takes over. Serotonin depletes, causing a new lover to start obsessing. Dopamine - associated with pleasure and reward - is going strong. Virtually all love poetry and pop song lyrics stem from this phase. You can't stop thinking about the other partner. Nothing else in life matters. As Dr Fisher explains, no one kills themselves over lack of sex. It's a different story when losing the affection of someone you are obsessed on. In the third stage everything settles down. You're in it for the long haul. Again, different hormones take over.
So here's what you have to figure out: Is it personality or merely phase II not thinking with your brain? If the former, run like crazy. If the latter, you need to figure out - is it obsession or is it love?
We often confuse obsession with love, and from what I hear from you it sounds like your boyfriend doesn't know the difference. If it's just obsession, then once the obsession dies down he won't be there for you. You can take that to the bank.
Even if it's genuine love, you need to be setting strong boundaries, namely:
1. A strong reminder that you hardly know each other. Back off.
2. A strong reminder that you need your space and he needs to respect your space. Again, back off.
Phase 2 is no time to be talking about marriage or moving in together. Things need to settle into phase 3, and that takes time. If your boyfriend doesn't accept this, then he is way too immature to consider getting into a long-term relationship with.
I know you have strong feelings for your boyfriend. But also consider, you may not be thinking with your brain, either. In phase 2, we will rationalize just about anything. I know - I've been there.
Also consider: Phase 2 is difficult enough for so-called normal people to handle, especially men who are hardwired to be the initiators. Phase 2 combined with bipolar is a recipe for disaster. We over-react and under-think. We get volatile. We are personality in abundance - super-fun to be around, highly romantic, great in bed, as well as easy to anger. Also, with bipolar, there is strong evidence that our fear circuits are vulnerable to ove-respond. Obsession on top of fear (of you not being at his beck and call) is a disastrous combination.
Your boyfriend may well turn out to be Mr Right. But you won't find that out by giving into his irrational whims. Lay down the ground rules right now and see how he responds. Then proceed very slowly and carefully.