How should this work?

My husband and I opened our 10-year relationship this year so that I can try dating women romantically (not casually). What I'm wondering about is if there is any way "exclusivity" is normally applied to these situations. When I dated before meeting my husband, I would focus on dating one person at a time. Now, too, I wouldn't want to go on multiple dates with multiple people at the same time, and I would like to be able to expect the same thing from my partner at a certain point. So, me and this other woman would date each other "exclusively", but my husband also exists. Is that unfair to ask someone for?