aggressive dog and i’m not sure what to do

For context the dog is a Australian Shepherd mix who is about 3.5 years old. We have had aggressive issues since about 6-7 months. My husband is the one who typically takes the brunt of it. He has been bit more times than I can count. I have been snipped and growled at a few times. I can't tell if it's fear, aggression, reactivity or what. He's scared to grab his toys off the vents in the house. He will bark and jump at you if you leave the room and close the door with him on the other side (think leaving to go somewhere or we have baby gates that he's blocked from going into the kitchen and our son's playroom. He has not bit our son but he has growled at him but never in close proximity. It's usually when he is in his playroom throwing a ball around and the dog will start barking at him. His crate is in our bedroom and the only way we can get him in the crate is with treats (which is manageable and not an issue) once he is in the crate and he hears one of us enter the room or if my son is being particularly rowdy on the bed (walking around and doing standard 2 year old things) he'll start barking like crazy and almost try to jump out of the crate. He's weird about his paws being touched and he also is weird about if you touch him at all. He has random quirks that you often don't find out about until he's growling at you. I will say it is nice that he at least growls first. As of right now, we have come to the agreement that if it's my husband bit then he can deal with it. But if either me or my son get bit the dog is gone. However, I'm currently pregnant with my second and as I was taking him out this morning he stepped in poop and got it all in his paws (again he does not like his paws to be messed with) it took me a good 10 minutes just to convince him to let me clean his paws and even then I still wasn't able to fully clean them and he was growling the entire time. I took breaks to reassure him and make sure he knew he was fine. I'm just really concerned because #1 I don't really want to wait for him to bite one of us before doing something. and #2 I am also super concerned about bringing another baby in the equation. It was fine when I just had the one because my attention was undivided however, when this second baby arrives my attention will be divided between the toddler and newborn. We have tried aggression training in the past and it helped with his reactivity walking around other people (he would literally lunge and bark at people making walks almost impossible.) But it has not helped at all with his behavior in the home. It's really tough too because I'm basically ready to be done with him but I do care about him and if we don't have him that would mean he needs to get put down. Which I'm not a fan of but knowing his behavior toward other people I know that he wouldn't do well with strangers. My husband is absolutely against doing anything unless something bad happens but again I really don't want to wait for that. Does anyone have any guidance? Or has anyone been in a similar situation?

I should also add that he does not resource guard, and does not have any health conditions that would cause aggressive behavior. There were I believe 7 pups in his litter and at least 2 of which have already been put down due to the aggression. I believe I included everything if not I will add as needed.