I really hate to tell you this, but "love" -in its cheesy-romeo-and-juliette meaning, can't last forever.
Someday, you're going to wake up and think that you don't really "love" your partner as much as you're used to them being around. You care for them, you want them in your life, but hearing their voice on the phone doesn't give you chills and seeing their eyes doesn't mean searching for that sparkle anymore. If you fight, you don't stay up all night trying to figure it out.
Now, you no longer see a perfect person. Their flaws are no longer "sweet" and your fights are not "cute". It is just a part of the whole "we're a team" thing and team members fight.
It might sound like it's a bad thing at first, but let me cheer you up: it's really not!
Because now this person is more than sparkly-movie-like love. This person is the real *Ish*! It's the person that put up with you in every state of mind you've been through; when depressed, when too excited, when all talky, when your jokes are not even funny, when you're a mess and make them feel guilty about it, when you're quiet and careless, when you think you know it all or have no clue... this person stuck around. They didn't walk away. They didn't step back. They were right there trying to understand, trying to remember why they've loved you in the first place. This person never sat aside and just watched as you ask yourself existential questions. Instead, they were right beside you looking for answers even when you're not. They put up with your moodswings (and man we girls have a lot of those), with your hormones, with your emotional rollercosters. They were even there with a box of choclate and goofy jokes just to make you feel better about yourself. Now, your flaws are no longer sweet and to them fighting with you is no longer cute. But they still choose to stay. Because, they've accepted you the way you are. They are not looking for an excuse to leave, they are efforetlessly sticking with you through the good and the bad.
This person is now beyond love, passion, and sexual attraction. They are now essential. You know how no matter what your parents do you can't but want them in your life ? You can't imagine life without them. You miss them all the time and you are forever grateful for them. Now, this person matters just as much. You might be used to waking up next to them. You might not realize how much their presence makes you happy. But it does. They made such a difference in your life that you deep down know you wouldn't be you if not for them. Now, you can start being grown ups together. You are now a much stronger team. Having them in your life never seemed as liberating. You, now, can be holding each others souls so tight without the need to actually hold hands.
So when it's all different and you find that you enjoy a cup of coffee with just yourself don't freak out. Life will surprize you. Keep that in mind. It'll surprize you with so many things you never knew about. Even within yourself. So, when it does, just try to handle it as well as you can. And most of all, learn and grow and always stay prepared for the next chapter as it might be just a little bit different from what you expected.