Most of the posters above seem to think that your BF will improve with experience. I disagree. SKILLS improve with experience, but ATTITUDE is unlikely to change. A little of what you describe (such as beginning the ascent with too little gas) is a matter of skill, but much of what you describe (leaving you alone, refusing to do a safety stop, etc) is a matter of attitude.
Scuba diving is a relatively safe activity when all safety procedures are followed but the risks carry severe consequences: DCI, AGE, drowning, etc. Scuba is a buddy sport, not because it's fun to share the experience, but because you are dependent upon highly technical equipment, and your buddy is carrying your spare equipment.
My advice, since you've already communicated your concerns, and your BF has demonstrated that he does not take you seriously, is stop diving with him immediately. Or dive in a group where you'll always be near one or more other divers. And if he shows you as much disrespect above water as he apparently does below the water, he may be a poor choice as a BF, as well as a poor dive buddy.
As for him swimming on his back because he was out of gas, I use my snorkel once I'm on the surface. I don't know how common diving without a snorkel is, but I was taught to use one, and I've been places where they required that we wear them.