I think it is because honesty. When we Love and grow into it, we Start to get attached very much. Then we Start to Alter the truth, are getting afraid to loose and get pretty much Stuck in mind.

There is Love in higher Ages, but you have to Fight for it in Terms of honesty and challenges resulting from them. I think humans arent monogamic ( in General) but try and Go ahead to tell your Partner that you still Love him/her but also need something for a Change for your own Life. This could be pretty much the Definition of impossible 😁

Hope you get my Point. Stand Strong, things will help you to work them Out! :)