I have read all the posts and my fear is that this is not something new but something in him all along. The phrases,the lack of care for you,the selfishness, the rude manipulative abusiveness- I feel that you know all this but don't want to accept it to be as it is; I wonder have you ignored a lot and want to view him as your best friend but in reality he's your best friend as you put up with and do so much to keep him happy,perhaps at your own expense?(*when you said you were a people pleaser this increased my concern that this may be the case).
You said you effectively have done all the night feeds/minding with your existing boys and that he has rarely collected them.from.school/done dinner (or rarelydone something like that). So again, despite you also working full time and earning more it is you and your family doing the heavy lifting.
He now speaks all about himself and his freedom/life/himself. This is before the shockingly abusive deployment of suicide and blackmail clauses in speaking with you and BTW those phrases are actually designed to effect pressure on you to abort: telling you he won't love the baby,won't help with baby, won't look at 'it', won't 'go near' you, doesn't know 'what he'll do when you start to show', will treat baby differently to existing children, all the work with bsby will be yours and also if the baby has any SN that the fault for that will be yours (*this is also deployed as a further guilt tactic to effect coercion over you so you abort ); that you will be affecting the marriage and boys (ultimate prick guilt trip attempt).
I understand that reading all these comments about words that have come from your actual husband is a bit overwhelming and you likely feel trapped,stuck,overwhelmed and DONT WANT to leave him.
But does he know this and has he been in a position of kind of power over you for years now? Think about this and genuinely I think it is you that needs the counselling to give you the strength to see options.
I know you likely only want an immediate fix and to be told you're making teh right decision but the source of this issue appears to go beyond this one factual circumstance.
Saying he doesn't 'want to share you', going on about him killing himself unless you effectively do as he says and all the other basal manipulative approaches mentioned by you and emphasised by others, all point a certain way: manipulation and control out of general abusive ans controlling nature- which you may have ignored by now- or some kind of freak once off reaction that is ongoing and for which he is making no apology and totally disregarding of your feelings and health and disrespectful in the extreme towards you.
I too actually wondered if he was actually having an affair if this is out of character. The fact he says he'll never leave but almost suggests taht you may not want to be with him gives me further basis for suspicion. Also the fact that he's helped so little previously and his comments and behaviour make me wonder whether this is a pattern but usually more subtle.
You have terminally ill family and 2 children ,recent deaths and are pregnant and with a full time job so your head likely can't take upheaval on family front or even going there but for what it's worth I would absolutely be seeking counselling but choose your counsellor wisely as you need someone who preferably is a psychologist or very well experienced psychotherapist .
If he becomes involved it will become apparent to you and counsellor what is true or not but you need to go there for yourself first. He will likely resist but if he sees your strength it may eventually produce a whole new husband,but unlikely.
Meanwhile teh only things that are pure ans will be there and love you unconditionally are the 3 children you have. As another poster said- the choice seems not so difficult: pick the baby if a choice needs to be made.
Would you pick your existing children or husband if he said it was him or them?? *Surely to even place you in that position illustrates the level of manipulation and horror you're being faced with by a man who is... your actual husband...(or who you thought had the qualities you wanted in a husband when you decided he could have that place I your life. This isn't irreversible you know..)