Yea so a few things.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4854098/
"Role of estradiol in eugonadal men
While estradiol has been shown to have a positive effect on libido at low levels of testosterone, a limited number of studies have looked into the effect of estradiol supplementation in eugonadal men and reported conflicting results. One study with continuous estradiol administration in men who had normal testosterone levels showed decreases in sexual interest, fantasy, masturbation, and erections.11 In contrast, a randomized, double-blind study conducted on 50 men ages between 20 and 40 years demonstrated that sexual activity was unaffected.12"
Proviron has some anti-estrogen effects. It will help with low libido from deca as will caber.
The thing is you can also have low libido if you estrogen is running out of control. 600mg/test plus 40mg/dbol a day leads to a significant amount of aromatization in your body causing high estrogen levels.
I am not surprised you have gyno symptoms as id guess your estrogen is pretty high. Have you done blood work? What dose of AI were you running when you crushed your estrogen levels and how do you know you crushed them? Bloodwork?