For some reason, I always thought you were woman
as I thought your avatar was some handbag or something. Maybe I just have bad eyes so forgive me for it
.
Now unto your post, I know you are trying to help her because you make more than her but you are actually doing more harm to than good by even paying her own bills for her [ Insurance, cell phone].
Let her take care of those bills herself instead of shopping etc. By letting her do that, she can start learning how important these things are. Also, you need to find a way to teach her the concept of money instead of her thinking of it as some sort of an attack.
Don't get married yet as you guys are not financially compatible based on your post until that is resolved. If you get married now the way things are, she will never change as you have set the tone of how things should be done from the get go.
Those gloves would be a very oddly shaped handbag
It sounds like you've made the effort to be understanding of her, you've tried many times to speak to her, and given her opportunities to make some changes. It's been five years - as much as you try, unless she *wants* to change (it really doesn't sound like she does), it's very unlikely that she will change. I do think it's a good idea to stop paying those two bills; I hope she actually takes responsibility for her own finances. I think that would show that she is at least trying.
What seems most concerning to me, is what she would do if for some reason, you lost your job or for whatever reason, your source of income drops. You say that you barely have enough left over after covering for both of you, despite the fact that she seems to have enough resources to continue purchasing luxuries while leaving you to take care of neccessities. Would she be willing to make any compromises to support the two of you? This should be a team effort; it's unfair for one person to be unwilling to even talk about such an important aspect of the relationship, much less refuse to act.
As for how to approach her...maybe start about savings first, mention that you're build savings like before, which will provide a good buffer for emergencies for the both of you (or maybe retirement, or vacation - whatever reason it is that you are currently saving). So in order to do that, you need to put away that percentage of money from your income. In order for that to happen, she needs to pay her own phone and insurance bill. If she protests that she doesn't have the money to do so, maybe you should ask her to add up her fun expenses and see if that sum doesn't cover it. I agree with you that her portion of the bills should be more like 1/3, but this will be a good baby step towards that. Hope that's maybe helpful?
I have to say that you are an incredibly patient person. Honestly, if I had a boyfriend who was like that, I would have left a long time ago.
Well, that clearly looks like boxing gloves to me, but I am wearing my glasses so that helps. 
As for your GF, you say you don't think she knows this is the primary reason for the lack of marriage. Maybe it is time to clearly spell that out for her. While you are at it I would say that you 2 need to set some rules and guidelines for your future finances. Since you are the responsible one, I would say for you to take responsibility for paying all the bills. Add up all your expenses and decide on an amount she will pay each pay period to contribute to the bills AND the savings. She should be responsible to contributing to that as well. I know you guys hate the touchy-feely stuff, but you REALLY need to make it very clear how much stress this situation causes for you, and make it clear that this will be a dealbreaker if you two can't come to a compromise. It sucks to break up over something that should be so simple to resolve, but if she refuses to change at all and you can't live with things the way they are, that may be the only option. Also make it a point to sit down together once a month to review the expenses together.
Try to make sure you approach it as an open dialouge, find solultions that will work for both of you if she is willing to contribute to the conversation, and be open about your feelings. I get it, I almost have to beat the feelings out of my husband LOL, but we don't know if you don't tell us!
ETA: If you have it, I would probably go ahead and pay off the CC and close the account. It doesn't sound like you can trust her to not run it back up.
I appreciate the feedback from everyone above.
One thing I'm not worried about her is "running up" the combined account that we have together. It's a Care Credit account that was used once in 2012 and has been being paid off ever since without additional purchases. In fact, the physical card is long gone at this point and since it's Care Credit it's very limited in terms of what you could use it for anyway
I should add another piece of data to this discussion. We have a son together, which of course makes the option of potentially breaking up less than favorable. We have ZERO support system (family) in terms of help child-care wise, so one of us HAS to be home with him; it's impossible for both of us to ever work at the same time. We play the old "tag off" game where one of us comes home from work and the other will go to work. I work some pretty demanding hours for my job. There are days that I work 5AM-6PM and days that I work 5PM-5AM which of course makes it difficult for her to work around my schedule - I get that. There's been times that she's wanted to work more, but she simply can't due to our conflicting schedules. We make the best out of it.
I agree with those of you above that said the first step is getting her to pay her own car insurance and phone bill, 2 bills that I've footed for her for 4 years now. That will be a start if I can make that happen. I would assume that in taking on those 2 bills her shopping/spending will have to decrease since she really doesn't have a means of raising her income at the time. Something that I forsee could be an issue going forward though is getting her to consistently pay me back the $3500 that I paid off on that Care Credit account... especially if she takes on the two bills mentioned. She was paying a little over $200/mo to Care Credit which we agreed she would just pay to me once the account is closed.
Definitely going to need to have another talk very soon about this with her. I'll definitely take the angle that I'm having trouble with the bills while still contributing to savings as a result of the current situation that we're in... so something has got to change.
