There are two kinds of people in this world: Those who are sentimental, and those who are not. I fit in the first category of people. I get teary eyed over anything if it's attached to the smallest memory, even if it's a button (literally, I have a jar of special buttons). I can't throw away cards, notes, or pictures children have drawn me. But with being sentimental comes the curse of also being protective; I'm always afraid to lose something attached to a memory, so I guard it. I have a box of my favorite things that include notes from my mom and dad, a necklace from my grandmother, some string from a roll of twine my dad gave me, a letter from a friend, and a handful of other random items that most would find completely useless and should have been thrown away years ago, but if a fire were to break out, I would grab the box. I don't want people going through my box unless I give them permission, and I keep it close but not where it stands out. It may not be valuable to anyone else on the planet, but to me, it's priceless for the simple fact I feel like I will lose the memory if I lose the item.
It's fine to treat things sentimentally, but a lot of people treat others they are in a relationship with such as a mother, father, girlfriend/boyfriend, son, daughter, or whoever, sentimentally, as if a person embodies a part of ourselves we don't want to lose, so we grasp onto people desperately. My mother struggled--and still does-- with me moving out. My empty room left her feeling she had an empty hole in her heart because that part of being a mother was now over. She'll forever be my mother, but now she's a mother to an adult--not a child. The sentimental side of her longed to cling to that part of herself and therefore me, because I became her box. She soon learned that in order to enjoy the present, she had to stop clinging so desperately to the past. It's good to remember, but not in the hopes of reliving continuously a moment, a feeling, a point in life. This is why letting go of an ex-boyfriend/girlfriend can be so hard for some people because that person becomes the box that contains parts of oneself that is hard to let go and accept that being that person again is impossible.
Don't let anyone or any relationship become your box. Being sentimental is not about trying to still be the person you were a year or two years ago, it's simply remembering and moving on. Clinging onto people like a sentimental box of things hoping that person or that relationship still makes you the person you were then, is foolish. Let people change, let people move on, let new people in, but most importantly, let yourself move on, change, and become new. Don't be afraid to lose your old self. Don't be afraid to lose the box.