I was telling my hubby about this thread. He reminded me of something else, that might be helpful to you both.
When a partner is feeling insecure, (heavy with emotion) probably one of the worst things we can do, is try to talk them out of how they feel.
We can be well-meaning, trying to give examples of how things 'really are' but all it does, is come across to the hurting person like : ' Your feelings are wrong, and unjustified.'
We learned, to let that person feel the way they feel. To not minimize their feelings, even if it seems that the green-eyed monster has taken over. Many times jealousy tries to get in bed with 'intuition', and the emotional party, probably does make valid points, in addition to some invalid points.
So, let the person talk, and have their say. Let them get it all out.
As long as, it isn`t harmful to those willing to listen.
Usually if it is chaneled in a healthy way, the person feeling all the emotion and fear, will calm down, think on it, and come back to the discussion knowing the things they truly felt, and what was just the fear talking. Reassurance only works if the person on the receiving end is looking for it.
Good luck !