Sue,
I have the same problem, I've been having hematuria for over a year now. I've had a prostatectomy, radiotherapy and surgery for urethral strictures. I'm waiting to see the doctor and then a specialist again, but due to the coronavirus crisis I need to try to manage it for the present.
Has your husband been checked for urethral strictures? I submitted a post on urethral strictures a while back due the hematuria I'm having.
Like yourselves, because I don't know what the cause is, I keep thinking it might be something sinister.
Best Regards