Hi.
Okay, so some of the advice I read so far was good and some sounded a little too dramatic. There is nothing abnormal about your conflict with your husband- of course he is indeed being selfish and inconsiderate but he is doing 'him' which is by nature what men tend to do (and check out how much more career success they have too! But, I'm not saying that to say we should imitate it, there are indeed other successes and women also by nature tend towards understanding that). Anyway, first, breathe. Be calm and remember that this is a normal conflict, he is being very male and that none of that means you have to let it go on because afterall, there is a point in men & women hooking up even though they are from different planets.
2ndly, it is important to support his needs as a man because in the end it will lead to better health in the marriage. His sexual needs, business needs and relationship needs.
3rd, it is extremely important that your needs are met. You have a need and drive to suceed in your education and career goals- shame on any woman that wrote anything to you to make you feel guilty about that. You do not want to end up with resentments because you had to give this piece up about your self when you had the drive and opportunity to do it. Pursuing this will propel you to match your inner and outer selves, thus making you a more whole person and a much better mother than feeling that life ripped you off somehow b/c you instead had to tend after child/husband exclusively. It's not about the career as far as money and that kind of success goes- although we'll keep that a bit of a secret from the opposite sex for they too tend to look at the concrete and tangible results.
Okay, so how to do it all? ... here goes. It is SO important to all of this that you started this change with his full support and a clear coversation about supporting each other's dreams. Start this next conversation by gently reminding him of that and how much you appreciated & still appreciate his support, etc (communication tip- Positive Reinforcement!). Then how much you appreciate that he is working so hard at his new business, how much he cares about making it great for you guys as a family, how hard that must be for him and that you acknowledge the sacrifices he's making for that, etc. etc. (communication tip- stroking the ego). Then move into how you wish there were a "magic" solution that could simply resolve his yours and your son's competing needs, but that us grown ups living in the real world realize that there isn't one. And that you trust that if he had really realized how much this current situation is compromising your dream, he would've handled things differently just like there is no ill intent on your part to compromise his dream. (Communication tip: Benefit of the doubt/trust). But that given the current amoung of emotional and mental stress you've both been experiencing, that it seems to you that the two of you need to re-think things and figure out as a team what you can be doing differently.
You are going to have to pray/meditate, etc for patience, love, trust, etc. before during and after this conversation. But you CAN do it and you really need to. His reponse might be "I don't know..." (and it almost should be, versus a schlew of self-defense) and you can say you don't know either and need his guidance and thoughts to try and figure it out (this puts it back on him). See what he comes up with, if anything. Whatever it is, make sure it's a real suggestion (not just, okay, I'll try harder) and again, not by attacking but by asking questions to draw him out more. Fully support whatever idea he suggests and try to make it work, if it doesn't, you'll both realize it and go back to the drawing board. And in the meanwhile, have a pocket full of suggestions possible. Even if he's not likely to jump on it (such as, well, maybe if we had a nanny that would help, would you like me to look into that?). He'll at least take more seriously that you are serious about finding a real solution to the obstacles in the way of your career goal.
And remember, this is NOT about casting your son 2nd to your career. Or your husband either. It's about looking in the long run to be the kind of wife and mother they really need, which is one that is happy and fulfilled. No other exterior "solutions" is going to really solve that- it is your task as an individual. Also, important side note- be sure to "contract" that time of conversation before you have it. Ask him can he make time for the two of you to take a walk/drive, etc and talk for 10 minutes. (or whatever is a realistic and manageable time frame). This way he is somewhat mentally prepared for conversation and not running out of it by "I gotta get to work/sleep/etc."
Sorry I sound so much like a therapist, can't help myself I guess since I am one. But certainly a wife and mother as well and I can definitely relate to your position! Uggh, I won't even begin to tell you my battle stories of trying to get through my Masters Degree. I know I've already gone on and on, but in case I don't talk to you again I want you to remember for the sake of your own sanity and spirit that even if you execute all of the above perfectly, you will still have to deal with this again and again throughout your education career. It is part of the cost you personally have to count. But be patient and be consistent with him, unless your husband is beating or otherwise seriously abusing you he is most likely a good guy that just has flaws. He will grow and come around if you handle it with wisdom and consistency. And it is a good & Important skill for you anyway b/c guess who's coming up next on that list?? your precious baby boy.
Good luck, N.