The fact that he's interested in seeing a marriage counselor tells you he's also interested in trying to make the marriage better. That's a whole lot better than the spouse who isn't even willing to try marriage counseling.
"The world" (books, friends, whoever..) often tells people to "protect their money" and "make sure you have your own money", even if people have no plans to separate (but especially if they're worried it may happen). One common belief is that "women are out to get all your money". Another common line of thinking is "husbands will often prevent access to money if women try to leave a marriage, especially an abusive one". Men or women, some spouses get so angry when the other even talks about "maybe making a change", they're the type who will immediately change things like bank accounts, only because they worry about the other spouse's reaction.
Sometimes the worry is well founded. Other times one spouse may not even imagine how angry the other will be when talk of unhappiness is raised. Sometimes, they're the ones who find themselves without access to any money at all.
If he didn't tell you he's been unhappy, it could be that he didn't want to hurt you, didn't want to stir up "a thing" if there was a chance things would get better on their own, hoped he could set aside whatever he wasn't happy about, or any number of others reasons. This is only personal opinion, but I think one of the most unfortunate things people often do is misinterpret the motivations of the other spouse. (That's why marriage counseling is probably the wisest next step you can take.)