In a startup there typically are no numbers to crunch, or schedules to work with, or any ROI considerations. You can't extrapolate from zero data points, after all. Startups are usually a binary play: either the product is good and people want it and the startup can grow into a serious business (with number crunching and schedules) or the product is no good and the startup folds.
That said in your relationship there should be very clear communication. Is it OK if it takes 5 years for your husband to find product-market fit? Is your husband supporting himself with his savings or are you supporting him? Does your husband's startup dream hurt your relationship with him? Are you disproportionately sacrificing for his happiness?
It's almost impossible for outsiders to judge if your husband is systematically working towards a realistic goal or whether he's deluding himself by working on a hobby project hoping the business side will somehow take care of itself.
Your husband can't expect you to support him indefinitely (if that's what's going on here). You can give him another year (or whatever you think is reasonable) and after that he'll have to suck it up, get a regular job, and work on his AI app during nights and weekends.
Frankly, these matters should have been discussed before your husband embarked on his startup. Startups are stressful even when everything goes well and many marriages don't survive it. If your husband refuses to talk with you like an adult then you need marriage counseling.