There are situations and people that will change your outlook on life. I have met a person and wondered where they were all my life. Ending up with the wrong person is how divorce happens and how any relationship ends for that matter.
When you are with the right person you never want to let them go. The only issue with this is trying to figure out if they feel the same about you. One-sided expectations or feelings can destroy you when you really want the other person to feel the same as you do about them. Over time feelings can change and you actually can fall out of love with a person but still care for them deeply.
Most people will not be honest and tell the person they once loved that they are no longer in love with them but they will always love them if too much damage has not occurred. The fire can burn out and when you try to bring it back a gust of wind comes along and blows it right out.
When changes happen in a relationship, those changes, will bring you both to the next level, level off or END. The outcome will depend on if you are willing to fight or weather the storm. The worse thing to do is lie to each other and become roommates. Let them go! Allow them to be with a person who wants to love them deeply as they would love them.
Time is something we can never get back nor can we force anyone to love us or stay in love with us.