Forever...is it possible?

Forever.
I've been thinking a lot about this during the past couple of days ever since the news of Al and Tipper Gore separating after 40 years made headlines.
Only the Gores know the reason behind their decision, and that's exactly how it should be.
But it made me think: does anything really last forever in this day and age?
The ideal behind being with someone until the moment you take your dying breath is beautiful. But is it realistic?
Part of the problem is that people change as time moves forward. And that often means that the person you were, say, at 20, is not the same person you are when you reach 40.
I like to think we evolve and grow as we age, and I believe this is where the problem lies. Change, in any form, is difficult for people to accept.
What happens when one person keeps growing while the other maintains the status quo?
I know there are couples who embody the ideal of 'forever' and I find that beautiful. There are stories of the elderly couple who when one dies the other follows not long after.
And I don't think forever has to do with love, but rather with passion. If you love someone, you will always love that person whether you are with them or not. But passion, is what keeps things lively and interesting. Without passion you are simply going through the motions.
And in all honesty, you have to ask yourself do you really want to spend 'forever' without passion?