I would add another caveat that if you’re in a committed relationship, you owe it to existing partners when starting up a new relationship to ensure that they’re comfortable with the change and feel that their relationship is honoured.

If you can’t do that it’s not actually a committed relationship, it’s solo poly. If you have absolute freedom to date anyone you want, the corrolary is your partners are left only with the choice to stay with the relationship as it is, or leave.