I would be interested to know what sorts of "things" you refer to.
I can speak to this from the perspective of someone in "her" position. I have a secondary partner with whom I feel drawn to do things that I do not feel drawn to do with my husband. This bothers my husband. I understand that it bothers him, so I pretty much give up on doing anything outside of his comfort zone.
If you care to share more specifically what types of things you mean, I might be able to say more.