That's a good story. No need to apologize when it's easy to read.
The feelings you are experiencing are normal. You may be able to work with them or you may not. There's clearly not one right answer.
I text Susan all the time. Most are just to let her know I'm thinking of her. She may or may not text back. If I know she's going to be busy, I typically refrain; not due to jealousy, but that I don't want to interrupt. I still always send her a good night and a good morning.
On the overall, my jealousy is always insecurity related. There are times I'm afraid she's going to end our relationship. It's completely irrational, but it's just something I have to deal with. It is exacerbated when I don't know whether I need to be around for her or not. The other thing I had to learn is that it's not a competition. She clearly enjoys being with you, and that's independent of anything else going on. You don't have to compete with her other flings. You just have to keep being yourself since she's clearly attracted to you.
Over time, I've gotten less and less jealous because I've been able to conquer the insecurity in this relationship. Try to identify what it is that is causing you the jealousy and see how you can adjust to it.
It won't be easy, but the level of communication you two already have will make it a lot easier.
Me: 41 straight male in a V with
Wife: Kay - mono female - married 18 years
LDR ex girlfriend: Susan - poly? female - 4 year relationship ended 9/29
Stakes - very intimate friend