In a similar situation 18 month old DS and 6 1/2 months pregnant - have you read anything on 'high needs babies' at all? It really might be worth seeing if your DS has these traits, mine does and it helps to know it's not anything I've done. Your DH is being ridiculous and extremely unhelpful, maybe he needs to spend some time with some other toddlers to realise tantrums are just a part of daily life and can't be caused by anybody else.
I don't think any child listens to the word "no" at this age, I have shouted on occasion (not proud but I'm only human) and I've found it makes it worse, usually happens when I'm busy making lunch or something, he becomes desperate for my attention even if it's negative. I'm trying to let him 'help' where possible (wooden spoon and a pan just like Mummy, lifting him up to see what I'm doing) - I think it makes him feel more independent to be involved and he 'behaves' better
one more thing, I've noticed that tantrums often happen if we've deviated from our loose routine, when he's hungry or tired for example. I've had days lately where I've stuck to the rough schedule below and not had a tantrum all day. I suppose a lot of it is trying to meet the needs before it becomes an emergency but they are going to happen more before they subside, that's just part of the frustration of understanding more than you can communicate
6.30/7 wake up, nurse, snack
8.30 ish breakfast
11 ish nurse, nap
12.30 ish lunch
3.30 ish snack
7ish dinner
7.30 ish bath, story, nurse
8 ish bed with sleep usually around 8.30
some days he wants/needs 2 shorter naps but usually sleeps for an hour late morning (used to do 20-40 min naps so things do get better) and he is starting to be able to 'self-settle' with me in the room
I do think things will get harder before they get easier when number 2 comes along, but everyone I've spoken to says it gets easier after the first year or so.. At least we'll have a vague idea of what we're doing and hopefully these babies will go with the flow a bit more!
I think it would be good to direct your DH to the parenting section of the library or get him more involved, I'd also be telling him I need more support rather than blame. I really don't think anything your son is doing at this stage can be blamed on you being PFB, all toddlers have tantrums and all need their mums, sounds like he has some growing up to do!
Best of luck :)