Relationship complications *possible trigger warning*

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That there is posted by my SO, his first part on here. My question, the mild issue that I'm having, is how to reconcile Hraith (the possessive, protective alter) and Darius (the happy bouncy alter). More importantly, I'm trying to figure out how to make them both happy and ok with how our relationship works. Hraith has an issue with certain things, like the fact that I saw him while he was sick and took care of him during that time. Darius on the other hand was happy for that, happy I care enough to take care of him.
I'm trying to figure out how to reassure Hraith that he can be strong and protective and even possessive of me (despite the open nature of our relationship), without ignoring Darus's needs or encuraging jealusy on Hraith's part when I'm with others. So far my SO has been with me every time I've been with another partner since our relationship started, but that might change as we'll likely be in different parts of the country for a bit. I'm looking for tips and suggestions. I love the bugger, and want to have the best relatiohship I can with all of them.