I'm also on venlafaxine, and have been for years. I've recently (4 months) started MMJ for my chronic pain, and it seems to offset the sexual side effects of the Effexor: (1) I have a libido again (2) I always finish now (3) and it feels pretty damn good.

The 3rd needs explanation for those who haven't experienced it; one nasty side effect is when you orgasm you ejaculate and feel NOTHING. It messes with the male psyche in a big way in my experience.