It doesn't sound like you have low libido. It sounds to me like you have a mechanical sexual erection dysfunction.
I don't think anyone can really help you with that outside of a doctor. You need to have your blood pressure and heart health checked. And yes, stress can cause this, but it is also one of the first signs of heart problems. It sounds to me like you have libido, and you have a great desire to put real energy and effort into your sex life, but there's a physical problem.
Thank you for your comments. What is the difference between low labido and erectile dysfunction and what causes this? I maintain good erections at times especially when waking up in the morning, yet when I'm with my man, it doesnt last long.