Hi! I'll be glad to be of help with this issue.
I can imagine how frustrating this situation must be for you. You are clearly in love with your husband and this is a beautiful thing. I want to introduce a possibility here you may not have considered. I don't know if it's truly the cause within yourself for this situation, but it will help you in thinking about this in new ways.
I wonder if your jealousy is so much caused by true jealousy or if it is perhaps subconscious fear and dread that is manifesting as jealousy. Let me explain.
Jealousy is a type of fear and dread: there is fear that your husband might be attracted to some other woman and you will be somehow "left behind", abandoned. There is dread that this might happen. You state that in 25 years there has been no reason for you to have such fear and dread. But now for the last couple of years or so you have developed this dread. If it was truly jealousy, it would seem unusual that it developed now as he hasn't become more outgoing from what you state.
However, he is now in his 70s. And while it is a sensitive subject, he is older and there very well may be the growing fear and dread in your subconscious of his growing older and something happening to him and you "being left behind" or abandoned, so to speak. It is really not uncommon for women to have fear about their husbands' health and longevity starting in the mid-late 60s. I deal with this in therapy in my private practice quite often with couples in this age group.
Okay, I wish you the very best!
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