OP, there are over four billion men on the planet. This one is a DUD. A fail. Nuh-uh.
He is worthless and has been handing you a pile of red flag warnings that if you continue with him he will make your life hell.
Some men gravitate towards a woman who has been hurt and damaged physically and psychologically - because they sense she is not healed and will be easily vulnerable to further abuse. Because THAT is what they crave.
His idiotic jealousy, insults, suspicions, attempts to control what you do, where you go and who you see are bad enough now in a LDR - but imagine how they would escalate should he move in.
You're not ready for a relationship.
Invest time and care in yourself so these creatures stop sniffing you out as potential prey. Because that's how he sees you.
Do not believe his ex cheated. That is clearly a fake alibi for being suspicious of everything.
Do not believe the sad heart thing. That's called love bombing and is designed to manipulate you into feeling bad.
Do not cling to any idea that it's a second language thing, misunderstandings etc.
It's clear: Control, control, control.
We can help you compose your strong, assertive, clear statement to him. Then we'll encourage you to BLOCK everywhere because realising he's lost control he may try to access you any way he can.
I'd suggest something like
'Hello x.
After a lot of thought, I have realised I am not ready for a relationship.
And as I am not enjoying this relationship, I have decided to end this one here and now.
Please do not attempt to contact me again as I will not respond.
Wishing you all the best for the future,
Your name'
Short, clear, message without being drawn into wrangling and arguments. No 'dear', no 'love from', and no 'sorry'. You have nothing to apologise for.
Stop wasting your time frantically trying to work on this dud. Start spending it wisely, working on you.