Gentlemen, I think you have already tried the little "blue pills" as they say in Switzerland
There may be a plant that can help you. Tribulus terrestris.
There are several forms but I (specialized in micronutrition) work with EPS. It looks like a blackish concentrate to dilute.
It improves blood circulation as well as tension while having beneficial on "bad" fats.
Some studies (but no tangible meta-analysis) announce an increase in spermatogenesis but here I do not confirm it.
If you need information about this plant or a dosage, you can ask questions.
It remains important to know that a chronic erectile disorder may herald cardiac dysfunction. Only a doctor can be helpful at this time.