Hi there,
This is my first ever response to a blog but I felt moved to do so as I can almost completely empathize and identify with your inner struggle which you posted.

Although I am not engaged I am living with my boyfriend and in a serious committed relationship with a man who seems very similar to your fiancé in that he does everything to make my life more comfortable, happy and is closely attuned to my needs. I have had two previous very close committed relationships both over 5 years ago and I cannot fully emotionally let either of them go for reasons of; intense emotional connection, complete similar interests and zest for life and that those relationships took place at a very impressionable, shaping time in my life…my early 20’s this last reason possibly being the clinging factor. But these feelings more strongly surfaced when I Moved IN with my boyfriend and when the relationship got very “real” to me.

It does not make it easier but try recognizing all that you went through during this first love relationship, there is SO much brain and emotional development going on during this time that (for very good reason) does not just dissipate and really shapes who you are today. Do NOT be upset with yourself that you cannot let go, in fact do no let go but be sure to move on, keep growing and keep loving with all your heart, despite the confusion and mixed emotions.

The best advice I was told by a wellness counselor was that “our brains are a problem solver”. To me this means that my brain is always going to try to find something to fix, not to say it does not want me to be happy but it is always trying to keep me safe. More than you may realize being engaged is momentous and triggers a lot of new and overwhelming emotions. Happy stress is nonetheless stress and your brain and body do not entirely know how to manifest that so to me, it seems normal your mind is driving you crazy with thoughts of a first love from 12 years ago. With this new “stress” trigger your brain and body goes into fight or flight mode but don’t get too flighty just yet.

Also do not burden yourself with thoughts of comparison between the two, consider it a part of the beauty of love that you have had such different encounters with love and if you truly feel your fiancé is not right for you you will find love again, when you are ready and willing. Just know, theses feelings are completely natural and very instinctual and it seems you have a lot of stress in your life right now but if at all possible do not let a beautiful love be one of them, gain strength from this love in every way possible.

Let these emotions drive you crazy, think of every outcome possible, getting back together with the ex from 12 years ago..what would that really look like? Are you the same you of 12 years ago? Or perhaps your experiencing nostalgia of a more carefree time (sans stress, work and life!)

Sorry this is so lengthy but just know what your experiencing is perfectly natural (not crazy) and maybe even necessary to move on to an even stronger marriage.