This is simple!

Do.

Not.

Fucking. 

Move the relationship.

To fast.

As in, they meet the first chapter, and in the third chapter they're already married and have kids.

That's not fun to read.

That's boring.

Personally, I don't even like marriage, I think it's a scam. When I see it in fanfiction, it just looses the mood, because when they get married I feel like the cute couples thing loses it's charm. Marriages can be cute! But don't rush things, hell, I'll write a wedding, but that's where the "happily ever after" thing stops. I find "Getting married and having kids" cliche, much prefer "Getting married and adopting a rescue dog" because that seems much more plausible in this day of age. 

That was my personal opinion on things, but if you are going to write a marriage, have it be after I don't know... 3, 4 years of them being together? 

Just by those standards alone I know I'm never getting married, I don't like dating people lmao.

But, take it slow. But don't drag it out. 

I personally like SillyPetals writing, because she has a good understanding of how long to keep thing fuzzy and cute, and when to raise the stakes. I mention her writing a lot, but she really is a great writer.

And the same goes for lemons.

Please do not write lemons as soon as the characters meet- that's gonna lead to toxicity. And it isn't fun.

OH!

NO RAPE! PLEASE! I'll make a separate chapter for that.

Long story short; Don't rush things, don't drag things out to long, and know when a story's wrapping up.