Jealousy Support Group
Jealousy typically refers to the thoughts, feelings, and behaviors that occur when a person believes a valued relationship is being threatened by a rival. This rival may or may not know that he or she is perceived as a threat. If you or a loved one may have an issue with jealousy, this community is a good place to start exploring the issue and get support. We're here for...
However, I believe that exes are ex for a reason and if one had any kind of relationship that stepped out of a friendship, its just healthier in my opinion to avoid any further contact.
The behaviours you listed, even though your partner did not respond, but him being in such a situation is bound to create feelings of insecurity.
Also if he has not placed a boundary or stopped those behaviours, its normal to feel more insecure about these things.
It might be better for you to be around when they interact? Or that you don't really want them to interact any more?
If they crossed the lines and seem to be at risk of doing so or make you feel uncomfortable, then partners should keep distance with that person or ex.
thats may take on these things.