It's fine to share what sexual/kink practices you learned from your bf with your husband, if bf is OK with you sharing, and vice versa.
However, if there are certain things you want to keep special, to only do with your secondary for a while, or forever, simple solution! Don't tell your husband what you did or are doing!
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
There's no lying in polyamory!
I'm a 58 year old woman with 2 partners:
miss pixi, my live-in gf, 36 (together since Jan '09)
Ginger, bf, 61, married, lives nearby (together since Jan '12)