obcessive thoughts/fantasies causing ED?

Hello all,
My case, I'm 62 years old in good health and not on meds. A few months ago I could get good erection while using a cock ring and visualizing (fantasy) my wife having sex with other men. When she would agree to role play by describing a fantasy encounter with another man I would get rock hard. Shes not into role play anymore and visualizing (fantasizing) doesn't seem to work anymore. I have had obsessive thoughts about her having sex with someone else since we were first married. I would get powerful erections using this fantasy until about 12 years ago and that when I needed the help of a cock ring.

I need to somehow change my mindset to focus on my wife without the use of the fantasy. She is still very sexy and sexual especially when she masturbates, that should be enough to make me erect, I get aroused including precum but not erect. Also I occasionally get rock hard erections while sleeping. The erection fades quickly upon waking. I have not tried V or C because of possible side effects. I have used Yohimbi and that gave me a raging hardon and horny feeling but too many side effects. I'm currently taking Zinc and vitamin C to help with testosterone level.

Any advice on how to reset or refocus my mind so its not dependent on fantasies that no longer work. Sort of fantasy addiction I would say.
TIA