Trusting is an issue w my hubby

Can anyone explain to me as to why I have to defend myself so much about being down for my husband to my husband. I don’t understand we’ve been married since 2020 been together since 2017. And he still don’t understand that I’m not going to cheat or lie or hide or flirt with any other man then him himself. I’ve done everything that I know or can think of to let him know by showing feeling seeing that I’m not going to do anything shady against him. We have a third baby together that is on its way. And I still can’t understand how why or what I am doing that can possibly ever make him feel threatened.