Recently began Trimix injections and I have questions for users.

I am 78 years old, widowed and new to sex after abstaining for 5 plus years due to my wife's illness. I started seeing an amazing woman about 6 months ago and recently discovered that we have a very strong physical and sexual attraction only to embarrassingly discover my inability to have an erection. I discussed this with my GP and he prescribed the typical oral medications with zero effect. I requested a urology referral and am seeing a nurse practitioner who has prescribed Trimix. I am healthy with the exception of well controlled diabetes. I have taken 2 injections so far, first dose 20 units and second dose 40 units as I got a minimal reaction to both in hardness and duration. I am going to make a third attempt using 50 units and my NP said not to increase past this dose and will re-evaluate. My girlfriend is a retired nurse and has some diagnostic concerns, as she puts it, in that no one has done a prostate exam in 6 plus years and she thought I should have a penile ultrasound to rule out vascular insufficiency before starting injections. I should mention that she made sure the injection was placed properly so I know that isn't a factor. She is concerned about vascular issues because we have extremely sensual foreplay and she can see that I am extremely aroused mentally and ready for sex but no erection. She is very understanding and patient, even downplaying the importance of penetration so I won't be embarrassed. She explained that the NP will probably adjust the medications within the mixture at the next visit. I want so badly for this to work because of the way we feel about each other sexually and otherwise. She doesn't think I had an extensive enough evaluation to have been given this medication. I would love to hear from other users who probably through trial and error arrived at an adequate dose of the most effective mixture so I know I'm going in the right direction.