I hope to god that I don't need to say this, Daisy, but incase you are thinking of staying with him because of the loan...
He will not be capable of having a normal relationship with you. Never. If he gets help and fully engages with it, there's a chance he could have a normal relationship with someone else, although he's always likely to be the insecure and slightly controlling type.
He will not be able to have it with you. Even the best therapy in the world cannot rebuild the boundaries he destroyed. He will always feel that he has a right to know where you are, who you are talking too, what you're doing. Even if he managed to avoid the temptation to bug you again, which would be extremely difficult after he normalised it for so long, he'd feel lost and upset that he doesn't know these things. However much you told him, he'd never feel "close" enough to what was happening. He'd always wonder if you were lying, and feel that you were holding things back.
In all likelihood, he'd wait a while and then upgrade to a "better" option, so that you were less likely to discover it. That's why there are such expensive options - nobody goes out and spends 3 grand straight away, but when their partner finds out and they move on, but the person can't live without that data, they pay for more and more covert services.
He will not be able to rebuild normal boundaries or have a functional relationship with you, and he may not be able to have one with your children, depending on how "bugged" they were and whether he listened to recordings of them. He may have the same isolated feeling if he's used to knowing more about them than they tell him.
You're also going to become complicit in lying to your friends and family if you hide this from them. He will have being surveilling their lives too, albeit accidentally, and he had no right to do that. They deserve to know.
The loan may need to be negotiated at a later stage, because for now, your safety really is key. The longer you wait to report this, the harder it will be, because he'll try to rationalise it and convince you that it wasn't that bad. It was. It is. He had no right to track you for two years, no right to lie to you.
You absolutely have to report it, if only because should you split in the future (and you really should leave now), you won't have any evidence of this if you need it. That would mean it would have no bearing on whether he can see his children or whether you can get legal protection from him. It needs to be recorded.
You should leave, though. Report it, and make plans to keep him away from you.