sometimes people grow out of each other
once the fire has burned out then it just cant be rekindled again
With respect, I don't think that you are yet ready to make a successful marriage. Ditto those who believe that marriage is about finding their "soul mate" - this is a fundamentally flawed premise.
To my mind, the only legitimate reasons for ending a marriage (or "lifelong commitment other than a marriage") are abuse, infidelity, addiction, etc, which weren't apparent at the time of the marriage, and not automatically so even in those cases. And of course if only one person wants to stay in the marriage, then there's not much the other person can do about that.
But what is a "commitment" if not a promise to stay together, even when the "shine" goes off? And you absolutely can rekindle a relationship; it's a matter of choice. Once you've made a commitment, it doesn't matter who else you meet, or whether things are as exciting as they used to be, because you've made a commitment. If you've only made a promise to stay together when things are wonderful, then isn't that a meaningless promise? Who wouldn't stay together when things are fabulous? It's the commitment to do the hard work to keep things fabulous that's the meaningful bit.
And I'm with some of the more "old-fashioned" contributors on this score: I don't think that people should even consider having children together outside a marriage (or marriage-like life-long commitment). Having children together is at least as big a commitment to each other as getting married, and more important in its implications. If a couple without children "fall out of love" and decide this is an adequate reason to end the relationship, at least it's only themselves that are affected. But once you have children, I don't think you have the right to get out of the marriage so easily. Nor do you have the right to stay in the marriage and be miserable; once children are involved, you're morally obliged to work at staying in the marriage and being happy about it. Again, I'm not talking about cases of abuse, infidelity, addiction, etc, or where one partner is not willing to work things out.
A successful marriage is having the right attitude to the commitment you're making, understanding what that commitment entails (ie being able to imagine what it will be like when the "shine" wears off, and being prepared to work at that), and ensuring that your partner shares your views on the nature of the commitment that you're making.
I've been married 14 years, my parents 41 years, and my grandparents 67 years (and counting) - all happily. I'm constantly grateful for their example; they're not "lucky" (well, perhaps my grandparents are lucky to have lived so long ), they've all made a commitment and worked at it.
(Sorry if this seems like a "rant", I've been steering clear of the controversy but just can't help myself anymore! No disrespect to anybody intended.)