Consider this post that had the highest number of "agree" ratings at the time of this writing...
Let go of the notion that your woman's body belongs to you in some way and that should help you deal with it.
Sorry to be blunt but that's the root of it. She's sharing something you believe belongs to you. Unless you are just scared she's going to fall for someone else the way she fell for you in which case you can just easily set boundaries like "no outside contact"
What Ember said is possible, but it does sound a little presumptuous to sound so certain that "ownership of body" is definitely the root of this, even with the "unless" disclaimer she included.
One of the most intense experiences I had with jealousy was right around age 19; it was really juvenile and stupid, but it is useful as an example I suppose.
My girlfriend's dad had bought her a car. He made it clear to both of us she was the only one who had permission to drive it. So for a few months, whenever we took her car somewhere, I didn't try to get her to let me drive and she didn't offer. This arrangement did not bother me. My car I drove, her car she drove.
So we went on a double date one night, she was driving while the other couple made out in the back seat. We stopped at a gas station, and when we came out she handed her keys to my buddy and told him to drive. This was because she wanted to be in the back seat making out. Not sure if that is because she had the notion that my body belonged to her, or her body belonged to me, or what.
Sadly, there was no making out. When she tried, I pushed her away. I got jealous, I got mad, I fumed, I sulked, when we got out of the car I was fighting back the urge to punch things, the other three took turns trying to "make it better" and wound up getting remarks like "why don't you go to hell/fuck off" for their troubles. Pretty much turned out to be a ruined evening.
She had been in a play the year before, and her part called for her to hug a guy; I didn't let on, but it made me pretty jealous. Letting my buddy drive her car caused the exact same feeling, only much worse (even though there was no physical contact with another guy). It wasn't because I wanted control of her automobile or her body; it was because she crossed a boundary for him that she didn't cross for me. She showed him favor she had not shown me, and that was reason enough to cause my inner alpha chimp to take the reins from me to try and get us back to our proper place in the hierarchy. So dumb.
Hormone driven teenagers on a double date aren't the same thing as adults on interacting on a camsite (hopefully), but aside from indulging in a stroll down memory lane, I guess I am trying to make the point that jealousy is not always rooted in "owning a female's body". Perhaps this is sometimes true even in situations like camming, where she is using her body to make money. Re-reading OP's post, doesn't it at least seem possible that emotional intimacy is what he seeking to keep for himself?
I have noticed in relationships that I was in, at least during the early stages, sex and emotions were inseparable once "love" switched on. I would totally lose interest in other women, be hyper-attentive to where her attentions were directed, hyper-vigilant about trying to keep her happy, that sort of thing. All emotions were much more amplified during this stage, including jealousy. All of this would die down as relationships progressed. Much more intense when I was younger too.
Honestly, this might be the type of thing that sorts itself out on its own. A camgirl I know quit because her SO "uprooted her from her life" and "demanded she give up her source of income". Some time went by, he is ok with it now (but draws the line at the outside contact Ember mentioned).
I wonder how old OP is. And also how long he has been involved with the model. And how many relationships he has been in.