G'day Pippa Pie, I too would feel betrayed by a partner taking three years to share their porn use. Takes quite a bit of planning and determination to hide that for so long.
I've heard of hypersexuality only recently, a search for that term may assist research.
When you observe/decide his immediate suicidal crisis is over, I suggest he and you create a safety plan for his suicidal situation, apparently there is an app for creating a safety plan ah here it is : BeyondNow suicide safety plan.
Once that safety plan is in place I suggest you share those feelings of betrayal and upset with him maximally and eloquently. Let him have it all, but just as politely and nice as you can. Then ask him if he wants to implement his safety plan. Be there for him and yourself.
I imagine one possible response...
If you've got to vent and shout/cry/scream etc, so be it, emotions can drive your response but not entirely control them. After letting him have all that he'll be more fragile again too, but that is, I think/feel, exactly where he needs to be. Fragile and honestly truthful enough to reshape himself into what you & he needs him to be, and with hope of reaching restoration of mutual respect and trust in whatever new shape the relationship takes.
If he'd come to you three years ago and shared he had an interest in porn, what might have happened?
Good luck.
