Is it in the norm for a physically healthy mid-40's male to NOT obtain an erection, unless he has direct physical contact (oral or hand stimulation) made by his partner?
By perfectly healthy, I mean, no pre-existing conditions or no medications being taken, in good health.

Yes perfectly healthy.

Do you lubricate without any touching like a machine?

First people are different some people may need different forms of stimulation. So if this is normal for you, it is normal ( for you)

If there has been a change from before I'd say it isn't normal. If you've always been that way then it may be normal for you. I would still expect there to be nocurnal erections without direct stimulation and, if so, this would suggest all is okay.

I guess what you are saying is that you can't get aroused unless there is direct contact to your penis.

I have never read any studies or articles about this.

Just my opinion, here, so... I think it would be normal for you to be aroused by thinking and looking in your 40's. For example, you are at work and a good looking young lady goes to file something in the bottom drawer, and she forgets to kneel and just bends over exposing her underwear and thighs. Something like that will likely give a man a twinge in he penis, no? Or, you are sitting and talking with a woman and she accidentally talks about how troubled she is and goes on to describe something very titilating that happened.

I think it would be interesting if you discussed sexual changes with a professional. **I don't know if this is you**, but I feel that the use of porn changes a man's "normal" responses.

Now, it could be that your girlfriend is just not mentally stimulating to you at all. That happens a lot.

Very best wishes, :)

Thank you very much for all of your advice!

Thanks for your compliment, never.

Thanks for your compliment, never.

Huh? Never?

She gave you a nickname :)

I'm really not the smartest of all people am I? :p

Keeping my mouth shut ;)
Just joshing you!