Tldr; current partner says I should "ghost" a coworker after learning we've been exploring a flirtatious friendship. I feel like I'm being punished because he can't cope.

Background: I (30F) and my partner (M32) have been together 5 years- we "identify" as poly, but aren't "actively" practicing. Meaning we haven't dated/slept with other people in a couple years. Since we've been together, partner has explored *lots* of causal sexual relationships and a couple more serious things. I've only explored a few things, none of which ended well. But we "paused" a couple years ago after I started sleeping with my partner's coworker (who he interacted with daily, but also gave me the "blessing" to see.) Partner had a really hard time coping and asked me to ghost the coworker. I did, because that relationship wasn't serious and we (partner & I) were moving states away anyway.

Current issue: I've been texting a coworker for a few days (we all work for the same small company but different departments with little interaction) and it's grown flirtatious. I don't know the guy well, so I asked him out for drinks to see if it was just a flirtatious work friendship or something else. My partner asked if it was a "platonic" meet up and I admitted my intent, while casual, was to sus that out over drinks. Partner got upset and set the boundary of no dating/sex with coworkers. Reasonable. I texted the guy to set that boundary and expressed I'd still like to explore a friendship.

This guy visited my office the next day-- legit business talk then a brief chat about my last text/boundaries. Very chill. But now partner says I can't text this guy or even talk to him at work. Basically ghost him. Because the idea of partner even seeing this guy is making partner feel uncomfortable (their departments have 0 interaction, so they only *occasionally* see each other in the parking lot.) This guy and I have done nothing but send a few flirty texts and have a couple casual convos at work. I'm mildly attracted to him, but idk if I actually want anything sexual with him. But partner is freaked and setting what I think are unreasonable rules for me so that he doesn't have to deal with his fears/negative thoughts.

It's not even about this coworker, really-- it's the unsaid-but-hinted expectation that I don't have *any* relationships that *might* trigger partner's anxiety. An anxiety that I'm pretty sure just comes down to "I don't want to share you." I love partner very much and I want to be empathetic...but I'm kinda pissed.