It is easy. It is because all girls exposed to a guy who is 'serious' about her will immediately feel that he is demanding fidelity immediately and she will feel boxed in.

Imagine the situation for yourself. It is quite disconcerting to be treated like a proven saint because you know you are not a proven saint but a normal human being. Also, trying to live up to being a proven saint who breaks no rules is actually pretty boring. Many guys believe they can become proven, obedient and reliable saints, which is why many guys like the military, where they obey orders and have order and consistency in the relationships. But they should avoid being like that towards girls, especially ones that he risks falling in love with.

Also, she knows that if he treats her like a saint, then pretty soon he will discover that she is not one and she does not want to be around for the fallout that the lightning strike of enlightenment will involve. What she wants is for him to find out all her own peculiar characteristics, quirks and foibles and nevertheless accept them or accommodate them sincerely in some way or another. She does not want all her personality traits to be undiscovered and trashed and ignored by attempting to fulfil his demands that she be as reliable and serious as he is straining the life out of himslf to be. So the odds are that any girl who has connected with a 'serious' guy will want out. She will lose him.

What he should be doing is to be realistic. What do I mean by realistic? He should realise that girls are different from boys. Girls do not keep a table at home and write up all the times he faithfully and dutifully did what he said he was going to do. In other words girls do not expect or want to build a business partnership with anyone when it comes to a starting a steady love relationship.

There are half a dozen stages in the relationship before getting to the tough stage of planning the week for who will buy the groceries, who will change nappies, which week is his for cooking dinner, and who will take out the trash today. She wants to get to know him well and experience and enjoy life with him first.

If all the first 6 stages go well, then there is the strong likelihood that they will be able to manage the bringing up children stage. By being 'serious' from the start he is putting the cart before the horse.

He needs to snap out of it and stop viewing the girl that he likes as a prospective business partner. Girls hate being put in a box. They want relationships, however shallow they stop at, or however deep they become, to grow organically and through common, unforeseeable and pleasurable experiences. She does not want to be in a jail and have a highly constrained 'secure unto death' relationship with her jailer.

Therefore he should cut out the 'serious' behaviour altogether and make NO moves towards a steady relationship and should actively see and meet other girls and have other hobbies until she realises he is the one to start to get to know better and maybe start going steady with. At that point she will demand to take more of the space in his life and will demand a steady relationship. (Even then the process is far from finished, if it ever is. :) )

But this is a crucial juncture to beware of. Particularly at this stage, this could be a trap for him. She may not realise it and may want to both have her cake and eat it, i.e. she may unconsciously want him as a steady partner but want to sleep with other guys at the same time. To avoid that trap he should first ask her whether she realises that faithfulness must go with the steady relationship. If he does not do this then he is setting himself up for heartbreak when they go steady and yet she sees/sleeps with other guys. If he cannot broach the subject then he is not ready for a steady relationship.

If she wants to go steady with him but recoils at the demand for faithfulness, then she is either immature, not ready or not worth having a steady relationship with. Then sadly, he should walk away until she comes to her senses, which may be never.

And if he has foolishly isolated himself and has seen only her up to that point, then he will not be able to shake off the memory of her as easily. All while if he has kept up other female contacts and other hobbies, he can forget her easily and sail on with his life, instead of becoming a case for the psychiatrist to sigh at his depression and prescribe some stupid drug.