Okay NAS. Here's a can of worms I've done opened like the Moron I am. Any advice?

I've been dating my partner for months now. I recently got out of a relationship about 3 months ago. Before that, I was in a Polyamerous 3 way relationship. I haven't seen my partner in about 5 months give or take. But the issue that I'm trying to deal with is that he's got the back bone of a Canary in a Cat Shelter. It's difficult for him to voice his opinions and even when he does, it rarely helps. I try to give him advice when he needs it, but I feel like maybe the advice I'm giving him may hurt him in the long run. I'm not afraid to stand up for myself but I'm not as outspoken as I'd like to be. And I don't want to tell him to do something that will get him into trouble in an already bad situation. After all, the things I tell him that I feel like he should say or do in a particular situation may work with me in my proudly raised outspoken family, but he was raised in a more passive family I think. The same issues he's dealing with could be solved very easily in my family if you don't mine telling someone where to shove their additude (And 9/10 times I don't), but I don't think it's the tactic he needs to try. I've having trouble figuring out ways to help him and give him advice on how to speak his mind and not sound like a total A-Hole. Telling him to turn the other cheek hasn't helped. Anybody got any advice I can pass along?