@Sjrl1
Please know that even if you were to take the test, it would not change his mind. Do not take the test. Challenge his thinking instead, in a calm, reasonable voice.
This mindset of his is completely irrational - be very careful.
It's based on jealousy. He wants to feel he is in control of you because you're the higher earner now, whereas he has not been a financial success story. Someone who seeks control in such a blatant way, showing such mistrust and hostility toward a partner of so many years, and such a complete lack of self awareness, whose mind has apparently lost the ability to filter irrational thoughts needs to be handled with care.
If you feel comfortable/ safe, tell him either he trusts you and stops the behaviour or he packs his bags and leaves, and the alternative to that "either/or" choice is that he sees a psychiatrist.
Make it clear that you are not going to put up with this any more.
If there is any violence or threat, either to you or to himself (cutting, suicide), or to anyone at your workplace, do not hesitate to call the police.
If you find you are the subject of surveillance by him (tracker in car, keylogger, cameras hidden at home), call the police.
If you don't feel comfortable/ safe challenging him on this, I think you need to get used to the idea that your relationship is over, and start finding support as you approach the formal, legal dissolution necessary.