I’m exhausted and I don’t know what to do

Long story short my husband barely helps around the house, and when I ask him to do anything for me he gets irritated and snaps at everyone. I have a 2 year old son with autism, a 1 1/2 year old who is going through terrible twos and I’m almost 8 months pregnant. My pregnancy is high risk and if I do too much my hips give out and I have made myself throw up from doing too much. We’ve been to couples therapy, I’ve told him how I feel and that I am scared of him and he says he will change and doesn’t. He took off a week from work to “help” me because I was sick with an upper respiratory infection and he played video games and read anime on his phone almost the entire time. Nothing was cleaned unless I did it, I’m just so exhausted. He told me last night that I only do the bare minimum for our kids when that is the complete opposite and it really hurt me. I don’t know what to do, I don’t know what else to say, this man lets our grass grow taller than our dog so I have to beg my grandfather to help me do it, he lets things sit around and mold. He is not reliable and definitely a procrastinator. He knows it too just doesn’t want to do anything about it. I’m anxious about the possible early arrival of our daughter since I’m at risk for preterm labor because of my cervix. Again I don’t know how to cope anymore.