Complements are free, use them. Flowers are worth their weight in gold. They are best used when their isn't any reason (apology, holidays). They're still good for those things but they're better for 'out-of-the blue' I love you stuff.

My stock joke now, when someone asks how long we've been married is - I ask my wife, she's says 40 years, then I saw to the person who asked, "It seems longer".

Hate is not the opposite of Love. Disinterest is. You just don't give a shit anymore. If you're fighting, you still love each other, and there's a chance for the future.