The outlook isn't dim at all!! That's a common misconception. My boys are funny and interesting and smart. And if they weren't any of those things, they'd still add to my life. You've got to process the idea that your son may be different. I mean, significantly different. That's hard. And sometimes that leads to grieving. But that doesn't mean that there is no happiness in sight for you and your wife or for him.
My recommendation is to take baby steps. It is really, really hard sometimes to get used to the new normal, so maybe instead of doing that, you just focus on his challenges and try to address those. At the same time, you have to honor who he is. It seems like your wife's bias is to do that, while you are the problem solver. If you both can communicate well, you'll be an unbeatable team. But that takes time. So for now, get him EI, and get him evaluated by a developmental pediatrician or neuopsychologist. It's what any dialed-in parent would do. Cross the existential questions of "why me" and "why my child" and "what about our future" later. You will cross them, I promis, if he continues to be delayed, even if it's not autism. Because...all parents worry, and worry causes arguments. But for now, try to focus on your son. And if you do that, the path to parental resolution will ultimately become clear. ((Hugs))