In my experience, although perhaps not as vast as some, I have realized that although not a rule, two of the most common complaints I hear from men and woman about why their relationships start to crumble and fade or fall apart, is in essence that they met someone who presented themselves in a specific way and then that person disappeared.
With woman their anguish is often expressed in "When we first met he used to make such an effort, he used to send me flowers and open the car door and jump at the chance of seeing me or doing something for me, I felt so adored and wanted... and now I have to beg him to do anything"
On the men's side what is often expressed is "She always used to make an effort to look sexy, to shave her legs, she was always up for sex, she used to say cool things that made me know she felt so proud and grateful to be with me... now she just nags me all the time, she's clingy, doesn't shave for days, wears frumpy 'comfy' clothes and whenever I want sex, she has a head ache."
The reality is that when we first meet the one that gets our chemistry bubbling over in that insanely fantastic "in lust at first sight" way, we want to present the best side of ourselves and we are willing to do anything for them. Our effort output is immense and its almost as if we transform into little drug dealers/addicts. We're giving freely and willingly of all the "good stuff" that gets the other one hooked and our effort output is at an all time high. In the past I might have said that men were the hunters, but times they are a-changing, woman have a hunting instinct too and what seems to happen is that the moment the 'deer's been shot' (so to say) both parties start to relax and get slack, the challenge has passed and so the thrill is slowly being diluted with 'perceived certainty' and the effort output minimizes dramatically.
What we tend to forget is that in life nothing is certain, everything is ever changing and if you love someone and don't treasure them and treat them with as much care and attention as they deserve and that you would like in return, then they will leave you (or you'll stay together, but stubbornly miserable).
Lets be honest girls making an effort to look sexy, makes you feel sexy and even if you're not in the mood for sex, dive in, it's so much fun your mood will soon change, let him know he is wanted and appreciated. And boys if you make her feel loved, wanted, heard and adored, she'll probably want to do anything for you and nagging will be a thing of the past.
So although the perks of getting to know each other should include 'relaxing into love' like waking up make up free, and him still looking at you as if you look so hot you are about to hit the red carpet. And you getting to know why he loves a certain csweet, and the very thing that makes it special makes you buy him one every week, just because the story of why he loves that specific sweet, made you love him just a little more.
Tip number 1: Be yourself from the word go!
If you are not prepared to make a certain amount of effort throughout your relationship, then don't do it in the beginning. We have enough expectation subconsciously built into our hearts and brains through fairy tales, films and advertising, so be who you are from the word go and when that someone still falls in love with you, then the only place you can go is up.
Tip number 2: Maintain your effort out put, always
Essentially the effort you make may change in the things you actually do for each other but the effort output should always remain on a high. In every relationship you will have days that the feeling of being "in love" beams out of you but you will also have days were feeling "in love" with that same person doesn't come as easily, and the quickest cure is first reminding yourself of why you love them in the first place (feeling gratitude for having them in your life) and then doing something that will make them smile and if you do I'm sure soon you will receive a little gratitude too.
May you all find love and cherish the one you love and my they cherish you, always.
