The Drama Queen Relationship

Hello all,
First timer here. I'm a 25 year old male and have been in my current relationship for almost 4 years. The first year of this relationship I was very happy and my girlfriend and I were very very close. We did everything together, however,at that time I was in college and went out every night and drank alot as did she. When I graduated, I ended up moving to the town where she worked and we moved in together along with one of her friends (another girl). I had every intention of marrying her at this point. We lived together happily for that first year. At the beginning of the second year, her friend moved out and we finally got a chance to live by ourselves. This is where the problems started cropping up. First of all, she is VERY messy and I always ended up having to clean up the entire apartment otherwise it would get so bad I just couldn't even stand to be inside it. I asked her numerous times to clean up after herself but she never made much of an effort. I explained to her that it is very important to me to keep a clean house. She suggested we get a maid......OK, why can't you as a mature adult clean up your own messes? Later that year, I cut out my drinking for the most part. I would have a beer or cocktail every now and then but I would not sit and drink myself stupid every night. She would make comments to me after that like "..why don't you ever drink with me anymore?". The more she drank, the more hostile and argumentative she would get. When it was time to go to bed, she would get very emotional and chastise me for everything. My feelings would be hurt and I told her this but she never seemed to care. The next morning when her "buzz" wore off, she acted like everything was fine. I would tell her that my feelings were still hurt but she still didn't seem to care, I just had to deal with it.
Another huge argument we have is the question of when we are going to get married. All of her friends are married or engaged, and she is giving me alot of pressure to do the same. I am not ready to mary this girl and I don't want to be pressured into making one of the biggest decisions of my life when I know in my heart I'm not ready.
I'm a very passive person and do not like confrontations, she is much better at making an argument than me. I feel like the more I try and state my case, the more she throws everything in my face. I'm always on the losing end. I finally had enough of feeling like I was wrong all the time. I went and saw a therapist and she told that the next few months for me would be hard and that I may need to move out and decide if this was the person I wanted to be with.
In the months leading up to my move, she kept trying to convince me to stay. She would make me feel insanely guilty about everything. Toward the days just before the move she said that this was basically a divorce and that in a divorce the woman gets to keep everything. Never heard of this rule myself but I was so ready to leave that I let her keep alot of the things I bought for the apartment.
After weeks of my girlfriend crying and arguing with me over my decision, I moved out. She even went as far to say that she was going to make me regret ever making that decision. To make me pay for moving out on her, she said that she should be able to keep a leather couch that I paid for, with little help from her. I didn't have much furniture of my own at the time so when I moved out, I had no couch, no coffee table, and no microwave or toaster. So I bought some living room furniture to which my girlfriend responds..."how are you supposed to buy an engagement ring when you've just spent all your money on living room furniture?". To which I respond that because she kept all of our stuff and wouldn't let me have any of it to furnish my apartment, I had to do something. Her response was..."well this would never had happened if you didn't move out." What am I supposed to say to that? Again, let's all pack our bags for the guilt trip.
I'll fast forward ahead to where we are at present time. She says I'm don't kiss her like I used to. Well, she's a smoker, I am not, I do not want to taste Marlboro when I kiss someone. With numerous pleads with her, she quits. We go on happy for a few more months until she reveals to me that she doesn't know if she wants to be married anymore and starts giving me the cold treatment but still says she loves me and wants to be with me. I can live with that, I'm not ready either. We've started staying at our separate places at night over the past 2 weeks and have grown increasingly distant from one another. She told me last week that she started smoking again. Then at a party she tells someone else that she never really quit and lied to me about it. This is all said right in front of me with other people around making me look stupid in front of my friends. As we leave to party she tells me, "We're not ever hanging out with those people again, I didn't have fun". It's like she's just trying to piss me off. When we go hang out with her friends, I try and make the best of it even though all her friends do drugs (I'm talking cocaine here)and I do not. I can be civil and have a good time even if I don't respect these people. When we leave their parties, I don't say to her that I'm not coming back to hang out with her friends. I understand that they are her friends and I will make a sacrifice to hang out with these people so she gets to be with her friends.
Which brings us to her jealousy issues, and this is a big one. I am a musician and play at local clubs around town. She is jealous of every woman in the bar because she says they give me "bedroom eyes" and are all staring at me. To which I am thinking, well I'm playing music up ON A STAGE IN THE MIDDLE OF THE BAR, EVERYONE IS LOOKING!!
If I go have lunch with a female co-worker, she will tell me that she doesn't like whoever it was that I went to lunch with. She questions all my female relationships like I'm sleeping with all of them behind her back. However, she has guy friends and hangs out with them all the time. She even went out of town to go hang out with a guy she grew up with and did I say anything about that? NO. I trust her, but she apparently does not trust me.
Last night, we go to a music festival. We're all dressed in shorts and t-shirts and she puts on a hippie looking skirt. We get home at around 11:45 and she asks me if I want to go to a bar and drink with her and her roommate. I say I'm just going to go on home but I'll hang out till she leaves. Well, she goes into her room and starts changing clothes. She puts on these tight pants and looks very sexy, alot better than the outfit she had on when she was with me. It made me feel inferior, like I wasn't good enough for her to wear that out with me, but she'll look her best to try and impress some drunk strangers at a pub.
I still care about her but I am feeling hurt and rejected alot lately. I suppose she is trying to make me regret all my decisions in the past year. One more item of note, when she goes out to bars with her friends, she always makes it a point to tell me exactly how many guys hit on her throughout the night......it's very very upsetting to me. I never tell her if a woman hit on me in a bar, most importantly b/c she would blow it out of proportion but secondly that I just don't care about if someone hits on me or not. I have a girlfriend and I don't get my self-esteem from random pick up lines from strangers at bars.

What's your take on this people? Any advice or insight would be helpful, thanks for reading.
David