At the very least, I have some very strong personality traits that damage my relationships which correlate with BPD. I was diagnosed with "Borderline traits" a few years ago, after I tried to commit suicide when I was in an IOP program. I tried to "kill myself" twice, and both times I can tell you were for attention and not wanting to actually die, and they were very lame attempts. I'm at least past that kind of immaturity. I know exactly what's wrong with me and that I act in unacceptable ways. I just can't help feeling abandoned and rejected all the time by my boyfriend and elsewhere. It is like there is an emptiness that at most can be temporarily satiated. I can say I am by no means suicidal as I once was, one of the main reasons being that I'm an avid Atheist (like yourself- which I greatly admire) and I see no reason to shorten my already infinitely tiny space of existence, nor make anyone feel responsible for my own emotional problems.
Anyway, he is one of the best boyfriends there is, and I've had so many childish temper tantrums and blame games in the past 2 years that we've been together that even he is starting to doubt whether I'm the best he can do, so to speak. He was once a good friend and absolutely enamored with me, which I blame partially on a facade of an interesting and funny girl. I feel that under this facade is a lot of vacuous pretentiousness and very little knowledge about anything. At this point, I feel that I'm being selfish by staying in this relationship. It makes me absolutely miserable to think about ending it, but I really don't want him to be stuck with me because he's a great person and deserves a great girlfriend (which is not me). He says he loves me and always will, and he doesn't want anybody else; he is content other than when I am like this. But the problem is that I will probably always be like this, or at least will for a long time, and he shouldn't be dragged along. I have come to the conclusion that nobody should be dragged along for the ride with me, so maybe I should stay away from serious relationships in general which render me vulnerable and thus emotionally reactive through jealousy and insecurities and distrust. Unfortunately this is also terrible because I have a tendency to get extremely depressed when I'm alone not by choice. I know exactly what it is too: the unconditional love that only a child gets from her parent, and I know I can't possibly expect that from a boyfriend, or friendship, or anyone else, especially when I'm a 20 year old female who needs to take responsibility for herself at this point. I really want to change very badly, but I don't think I have the means to go through the type of therapy that's needed for this kind of problem. I'm a college student and it's all I can do to keep up with my health and schoolwork at this point.
Do you have any advice or tips on how to control my emotions and behavior, as well as my situation?

You're not alone, Natasha! I hear what you are saying that you don't have the time or resources to get the therapy you need, but in my opinion, therapy is the first thing you need to do. I have been in therapy almost four years for BPD, PTSD, ADD, MDD, and OCD. I have made miraculous improvements and am now able better handle relationships. I now am starting to feel whole again, and this is what finally has brought me peace. I really hope you find a good psyhologist because this CAN get better!
Be well