I do not agree with that statement. Most “always” statements are a generalization, unless it is a proven scientific fact (ex: if you throw an apple up in the air, it will fall down). It certainly does in many relationships, but I think that has less to do with the “honeymoon phase” ending and more so that the people in the relationship turn out to not enjoy or like each other as they previously thought they did. Me and my partner have been together for almost three years our feelings for eachother have only grown. I believe this is for a few reasons that many relationships lack. Firstly, communication is key. Establishing guidelines to the relationship, such as whether it is monogamous or polyamorous or what the partners are comfortable with. If something your partner said upset you, it is much better to talk to them than let those negative feelings fester. Secondly, if your partner is also your best friend it makes the relationship last much longer. This means you can have fun talking and hanging out with them, but also have romantic feelings for eachother. I am not completely sure what is meant by intense passion in the question so I am unsure of how to answer that. However, I do not believe love fades when passion does. You can love a hobby, pet, or person but not be passionate about it, although it certainly helps to be passionate about it. I love some of my family members but I am not excited about them, I just feel like I want to protect them.