I agree with others who say we don't have nearly enough information. But I'll offer you two quick thoughts...
A. Generally speaking, men are encouraged to bury emotions - with one exception. Anger. Men are allowed to be angry, and we often bottle up everything until it all explodes in a burst of anger. You know him better than any of us, of course. Just be careful and be aware of any signs that he might be angry. It has the potential to be dangerous for you. (Again, this is a HUGE generalization.)
B. Are you on strong financial footing? Do you have your own bank account, for example, or do you only have a joint account? I ask because it's also possible that he has decided ending the marriage is the best course of action. And if all of your money is tied up into a joint account, he can wipe you out before he leaves. Again, I'm not saying he will. I don't know him (obviously), so I can't say what's in his mind or in his heart. But as above, be careful; take some precautions as best as possible to make sure you can take care of yourself at least in the sort term.
Actually, one more point. I would like to strongly recommend counseling for you both. This almost certainly has a lot of emotion and baggage to unpack for both of you, and the best and safest way to do that is with a neutral professional. That said, if he won't attend marriage counseling with you then please go on your own. He or she will be able to help you sort through your feelings and thoughts to help you make sense of them all.
Good luck!
