@beingtakenforafool ^ this ^
OK, take a deep deep breath. Do not waste time wondering 'why'. It is what it is. There will be time wonder about that later, if you still want it. Gather yourself together and see that solicitor, pronto. Take a 'snapshot' of the finances, especially investments and any pensions he has and get educated on what you can expect in a divorce. Take your friend with you as a second set of ears. Your H is a mile or two ahead of you on this road you've just taken your first, unwilling steps on. You need to play catchup. Knowledge is power, forewarned is forearmed.
Two things to remember; keep your silence and keep your dignity. You'll be glad you did.
Do NOT tell him you are seeing a solicitor. And quietly copy any and all financial documents you can get your hands on. Hide them securely or get them out of the house if you can. If you can get the important documents out too, birth certificate, marriage certificate etc, rental lease, etc. He cannot be trusted to 'play fair', you must protect yourself any way you can.
Do not argue, rail, beg, or let him see you cry. Do not do the 'pick me dance'. Cold and quiet dignity is the way to go. To any questions or suggestions you answer "I will have to think about that" or "That will take some consideration". You will have to do an Oscar worthy performance, but you can do it. And in time that coldness will become real and the pain you feel now will turn to anger. Just give it time.
You can do this. You have reserves of strength that you don't even know you have.