Is it normal to have lesbian dreams every night?

Not really normal buts it's like a thing. I would suspect you may be bi but don't entertain that idea of your in a relationship. Bad things.

I have a lot of dreams where I fly.

Gay.

I've never believed that we should pay too much attention to dreams. I think for most well-balanced and emotionally healthy people, dreams are usually just the brain wibbling away to itself when it's able to take various random stuff seen, heard and done recently, jumble it all together and freewheel off to wherever the fuck it leads. Still, psychologists say dreams can give insights into what's going on in our subconscious, and I'm willing to believe that's sometimes true.

Many women who identify as straight and would never consider actually having sex with another women have sexual fantasies involving women. (ISTR reading that about half of straight women do.)

Your suspicion that your dreams have something to do you you embracing your femininity seems plausible to me. The other woman in your dreams could actually be yourself in disguise. She's your inner-vixen or inner-slut or however you want to think of the persona who's free to do things that your conscious persona never would because social conditioning makes you conform to some set of rules when you're awake and out in the real world.

As for your boyfriend's dream, that could just be coincidence, or maybe it's an indication of him feeling insecure. If you really should decide that you were a lesbian, that would mean there was absolutely nothing he could do that would convince you that you should stay with him.

Do you ever slip a finger up your pussy while you’re dreaming about it?

Dreams are weird. They probably don't mean anything. Or maybe they do and you've been bi all along! Who knows.