<human>: My inquiry begins with my boyfriend of 3 years and I discussing the possibility of marriage between us; no serious proposal, just the possibility. I thought about it for some time now, and the more I think about him and I tying the knot, the more unsure and confused I am about the idea. I'm 21 and I've barely talked to people in healthy marriages in depth about it. I come from a long line of divorces and miserable marriages, and virtually none of my friends are married.

So my married Redditors, I need some comprehensive advice. Some of the questions I have are:

* Someone once told me that "you just know." Is such a thing true? Is there a light that immediately goes off in your head?
* I love him to death, and I like the idea of marrying him, but my intuition is that now's not the right time. I believe love grows, but if I don't feel that way now, will I ever?
* I'm worried about the "people-change" excuse. People do change, so I can't preclude the chance of him and I just growing apart. What qualities in a relationship indicate such a problem will definitely/never happen?
* My boyfriend cheated on me once upon a drunken time 2 1/2 years ago. Never a problem since, BUT "once a cheater, always a cheater," right? Is this a deal-breaker or not an issue at all? Or is cheating a reality of marriage?
* People get married for stupid reasons, but what would be a matured and learned reason to get married? What's a superficial reason to get married?
* What's this love-at-first-sight thing that's so hyped about? Any contrary or concurring experiences?
* Lastly, any related insight would be much appreciated.

Could you distill the essence of the text into 1-3 sentences?
<bot>: what advice can you pass onto someone who is thinking about marriage? Is there any special way to know you're marrying the right person?