Please Help Me Reddit: I'm having serious doubts about marrying the love of my life; how do I deal with it?

First off: thanks for the time. Long time lurker, first time poster. This is keeping me up every night.

Second: I'm sure that you've all seen posts like this before, so I'll try and be as direct and as emotionally communicative as I can.

I love my fiancee. She's a part of me, a vital organ that I have serious doubts I could live without. We are coming up on our fourth year of dating, and while they were never perfect, we made it work.

Unfortunately, there are a few problems in our relationship that go beyond the death-of-my-single-life jitters.

We have a serious problem communicating. I can't, for the god-forsaken life of me, understand where's she's coming from unless she spells it out to a T. And of course, she is constantly frustrated with me for not understanding what the hell she's talking about.

Basically, I need her to spell it out. She can't stand that I don't get it.

For example: after we fight over absolutely nothing, Me: "I think we have a serious problem communicating." Silence. Me: "(Her name)?" Her: "I think you're being a little dramatic." Silence. Me: "This is exactly what I'm talking about! I mean why don't you just start off by telling me why you think I'm being dramatic, instead of telling me I'm being dramatic, because I have no goddamn idea why you think that way! Just spell it out for me." Her: "I can't always spell it out for you." Me: "YOU HAVE TO BECAUSE I HAVE NO IDEA WHAT YOU'RE TALKING ABOUT!"

And thus, we argue about arguing. Eventually: she spells it out for me, I see she's got a point (and she's usually right, goddamn it), and I agree. Problem is, at this point we're both so heated we just go to sleep mad.

This is the biggest thing for me. Almost all our fights are some kind of variation of this nonsense. I'm not a stupid man, but I have no idea what to do.

The other biggie is that I feel like she constantly doubts my abilities. This drives me INSANE! I'll try and keep this one short.

I write for a living. Her family asks me to come up with a line for the beginning of something important. I take 25 minutes alone to think about it. I come back in excited, and tell them. They love it. She immediately hates it.

She does this all the time, and refuses to see a pattern. When this happens, even if she's right, I see red.

If you have any idea how to tackle either one of these two issues please help me. I love this girl and I want to spend the rest of my life with her. If I can't figure these out, I don't know if I'll make it to the wedding.