I   I have just finished reading the book "The Ethical Slut: A Guide to Infinite Sexual Possibilities"
it covers Polyamory in all its variations and is a very entlightening book for an innocent such as myself.
The book starts off examining our western views on Love, marriage, successful relationships, Monogamy etc. It highlights that Monogamy is not really working, and that other civilisations had very different ideas about relationships. It looks at the reasons why we have sex, and what are the right reasons, and what are the wrong reasons.
The title includes the word Slut, with all its negative connotations. The authors try to reclaim the word and make it positive. I am not sure they manage it, but maybe the negatives are too ingrained in me.
Both the authors (women) are in Polyamorous relationships with partners of both sexes. They have families, are in their 50's, and have a wide circle of friends, most of whom they will sleep with, and all of whom know about each other.
The book looks at safe sex, safer sex, fuck buddies, sex parties, swinging, orgies, everything, but not in a shocking way.

it is certainly interesting, and gave me food for thought. I think I need to read it again. One of the basic tenets that the authors wrote however is that Polyamory works best if the primary relationship that one is in is sound and loving. Polyamory can be used to have needs met that ones partner is not meeting, but any fundamental problems in the primary relationship needs to be sorted out as well, otherwise the security and trust is not there to be able to cope with one person or both having other sexual partners.
The ethics of the book are that one needs to be open and honest, and respectful to all people involved.

My husband did ask me what I was reading, and I showed him the cover. Now I will suggest he reads it too, but I am not sure what sort of discussion this might lead to. I would like to start being more honest, but what is done is done, and there is no point in bringing up what is past. It is where I go from here that is more important.

let sleeping dogs lie is probably a good counsel for this.