Spider I think there is a certain naivity in your posts, TBH.
Yes, of course, it is possible to love more than one person as we love all our children. I can honestly say that I still love, or am very fond of, some of my ex's who have remained close friends decades after we split up. But I don't continue to sleep with them now I am committed to another man. This is because HE would not be happy.
But how does loving lots of men work in real life?
IME men are much less tolerant of open relationships than women- if they really love the woman. This is shown by your DH's reaction to your thoughts now. If they are tolerant, they tend again, IME as a woman in my 50s, to be not fully committed anyway, and looking to play away with permission.
Despite what you assume, I really don't have an issue with anyone who wants to live a non-monogamous life. I do though think that eventually as many or mroe people end up as hurt or disappointed as people in 1:1 relationships. I think it is a fantasy to think you can be close to someone and have sex without emotions being involved.
I am not alone in this- the sex expert Suzi Godwin has written about this lots of times in her books and columns in The Times. Getting close enough to exchange bodily fluids is not like having a cup of coffee- it involves emotions and you are kidding yourself if you think otherwise.
The more people who are involved in such a set-up, IMO, the more opportunity there is for one of them to be hurt.
IMO and it is only mine, that is why monogamy exists- not because of some social construct, but because it lessens the potential for people being hurt.