Polygamy

I haven’t been in a truly polyamorous relationship. I have been in in an open marriage, with set boundaries around the additional partners that we brought into that relationship.
From my own personal experience, I suggest thinking long and hard before going down this path. I’ve yet to see a relationship survive through the introduction of others. Mine did not last and neither did the other couples that we were intimate with. Nor did the others we knew who were polyamorous.
If you do still wish to look into this, you need to have open conversation between you and your spouse around boundaries and limits for both of you. I suggest searching for groups on polyamory as a starting point.