Perhaps you could admit to him how you feel, and ask him to tell you when he thinks you are being jealous or insecure. Of course, you have to be able to forgive him for telling you these things
! Ask him not to spare your feelings at all in doing this, because otherwise he is going to refrain for fear of hurting you. If your problem is fear of what he thinks of you, then ask him to tell you what he feels about you so that you don't have to guess.
For example, if he goes out with some girl friends and it makes you uncomfortable, tell him that you feel uncomfortable with it. Don't ask him to not go out with them, you can't enslave him to your feelings, just let him know that this is the way you feel. Admit that you are jealous, and that you expect him not to cater to your jealous feelings. Oh, I forgot that point. If you have a feeling that you know is irrational, then tell him about the feeling but don't try to force him to conform to it. Ask him to have the courage to not cater to your more irrational feelings.
The best part about this system is that it's all about truth. You don't have to lie, you don't have to hide, you don't have to be ashamed. You just have to tell the truth. These are just some ideas as to how you can go about it. Whatever you end up doing, be truthful about it.