This is becoming a little akin to Chinese Whispers. i.e. the meanings of posts become distorted as other people change the meaning ever so slightly and you end up with 2+2=5.
If you happen to be referring to my posts about SGB not being in a couple relationship, and an open relationship pertains to couple relationships, then I think it's fair to say that the OP should have made it an "open" post.
This is not the same as saying SGB or anyone else is not allowed to have an opinion.
FWIW although I am now married, I had an open relationship for some time in my mid-late 20s. I also had non monogamous relationships then too.
I suspect that most women have had 1 of these- the latter is called "dating"! without there being commitment or exclusivity.
OP I really don't see why you needed to ask anyone for an opinion or advice.
Your Dh has made it clear how he feels. If you sought opinions to somehow validate your own wishes for an OR then I think you are missing the point. What matters is how you and he feel. What anyone else has done with their lives, or their own morality, is totally irrelevant, because we are not you, and we are not in your marriage.
I suspect you will do whatever you choose- which I think means at some point you will be unfaithful, with or without your DHs knowledge or acceptance.