You don't need to be qualified as a mental health professional to recommend psychotherapy. If a man here complained of symptoms that made it sound like he was having a heart attack, we'd all tell him to go see a doctor, and to me this is no different.
And although the wife may need a psychiatrist and medication (I assume this is what "treatment" means), I was writing to the husband here who in my non-professional opinion needs help of his own, simply by virtue of being in the relationship with her. And for this talk therapy may be enough. (Obviously patience and luck are nice.)
As someone who has some experience here (on the past kid side), results from professional help come slowly if at all, and especially if there are kids involved, drastic hard choices need to be made that we shouldn't talk about here.
The best advice I would give here is preventative: carefully evaluate the mental health of your potential partner, including their family history, you really don't want any surprises later even if you are OK with it. This is in addition to checking for lifestyle compatibility; e.g. if you are a scientist obsessed with your work, make sure your potential partner is really really OK with that. And do you require extreme order in your life to function effectively (e.g. some autism)? Ya, that is something you also need to take up with your partner.