Well, the annoying answer is "it depends." :P No one here can give you a definitive time frame, as it's different for everyone.
One approach is to go about that the other way. YOU set a definitive time frame. Tell your husband that you need to be able to fully express your other relationships to be happy, and negotiate a date when those things will start to happen. Then he has the responsibility to work on his insecurities by that time. Perhaps leave a condition where he can ask for a little more time, but only if he's making some progress.
And it doesn't have to be a 0-60 timeframe. Maybe after 2 months, you tell your friends about your lover. Another month after that, you can hold hands in public. Baby steps.
Some things may never realistically happen. Lover coming over and everyone hanging out together could be one of them. It's your husband's home too, and his need to feel safe and secure in his home overrides your want to have your lover visit.
It may also be worthwhile for your husband and you to consider a "mono-poly" relationship. If he's not actually poly, what does he gain by spreading himself between more people than he's actually comfortable with?
“As I am sure any cat owner will be able to tell you,
someone else putting you in a box is entirely different
from getting into a box yourself.” —bisexualbaker