My love, your problems sound complex, but as you are beginning to see, not ONE of them is down to you.
Your H is vile, he begrudges parenting his own children, has no interest nor investment in your happiness. Your anniversary anecdote is so sad, you deserve to be treated so much better than this.
Your mother has in a way created this dynamic, your upbringing was so dysfunctional as to hammer your self esteem into the ground. If you were in an equal and democratic relationship you would be able to remind your H that YOU do your fair share of staying in when HE needs to be out, so therefore it's HIS turn. he being fair and decent would totally get this. He is neither, your self-image is in tatters, partly due to your parents, partly due to him. He has no right to get pissy with you about anything.
Your Aunt grew up in the same dynamic as your mother did. Your mother is an alcoholic, that may have been caused by her own dysfunctional upbringing. Your Aunt may be cut from similar cloth. Her failure to respond to your text speaks volumes about her.
You can use this pinch point as a catalyst, a turning point, a time to draw a line in the sand. Standing up to your H would be a good idea. If the house sale fell through, someone else could buy it, your mother would be fine, she might have to move, but there would be money there to do it. The reason your H is using this house purchase as a weapon is because he knows you are scared it won't happen and you in turn will invoke the wrath of your toxic mother. He is literally torturing you. If you shrug, and stop caring whether he buys or doesn't buy, refer all enquiries of it to him and say that he's taking all the decisions, and you know nothing, IF it all blows up, it won't be YOUR name in the mud. Usually when someone of the ilk of your H realises that HE is going to look the baddie, he will usually buck his ideas up...
I know that you have probably had a life time of being to blame for everything, and being outnumbered by toxic people in your life often convinces us that it MUST be us that is the problem. It is not. You merely grew up in a dysfunctional dynamic, and since then, as a result of what has been done to you, have only attracted toxic people into your life. They see you as a target and make a bee line for you.
What to do?
Your end goal has to be to get away or distance yourself from those that damage you, actually putting all of that into practice is a long road.
Start by looking at how people treat you and start to say NO. Start to refuse to let people let you down, and start demanding a little more equality/respect. Little tiny steps to begin with. INSIST your DH keeps his promise, or say that you will pop next door and ask a neighbour to come and watch your DD as he has let you down again. If all else fails, take your DD to the play, there is nothing else you can do, if she kicks off, you can leave, take her out, and then come home and take your H head off 
You can do all this. Really you can. I know how hard it is to see that when you have been terrorised and bullied for so long, but really you can.
No, it won't be easy, but it is VITAL for your happiness and ultimately the happiness and success of your children. Once you start to be a little braver, dysfunctional people see that they will get no-where with you and you develop your own Toxic Person Repellent
There are many, many of us here who have similar experiences to you, and as someone lovely up-thread said, we do care, very very much. Let us help you find your voice and your strength.
MN has been a lifesaver to me, in many ways, you can learn so much and really transform your life, you just have to trust and be a little brave.