This crossed my mind, as well. If he's wanting to take care of his aging mother, then it's unlikely he'll be able to have her look after your future kids.

Some of this is age-related. You're far too young to be taking care of an aging woman, IMO. As someone mentioned already, you don't know what "aging" will look like until it's in your face. She could develop dementia/alzheimer's, get a stroke, fall and break a hip, etc. Does he know something about her health you don't? My hunch is, he'll want you to take care of his mother and children while he's at work.

What do you do for a living? Do you have post secondary training? He's talking a lot about caring for children and an aging woman. What about your career, ambitions, and dreams?

If there wasn't such an age gap and you were established yourself (and maybe you are), then this scenario could be seen as admirable that he's wanting to care for his mom before she passes on. It sounds like he has a great relationship with her and treats her well, on the surface. She also sounds like a lovely woman.

What I'm not sure about is how YOU feel about her. Have you spent any time with her? What's she like? Can you take a trip with her prior to deciding if this would be a good fit for you?

If there's no hidden agenda, I don't think there's anything wrong with taking her on trips with you both, pending that he makes effort for you both to take trips without her, too. Worst case scenario, he'll have you look after her while he takes off "exploring the scenery" and that wouldn't be fair.

I don't like how he's comparing you with his exes. I suspect the age difference is giving him a sense of entitlement over you. Was any of this discussed prior to your wedding?

What makes you think he's being narcissistic? Can you give us other examples? Telling you that you ought to adore him doesn't classify him for having a personality disorder.. but the fact that you're questioning it makes me think you're sensing other red flags, and likely, rightfully so.