If the person your affections are directed towards is not reciprocating your efforts at least equally, you can safely assume that they are:
1. Not that into you.
2. Keeping their options open.
3. Multi-tasking on a grand scale.
In any of the above scenarios, you don't have to waste your time trying to figure out why they didn't call or contact you like they used to, or why they are full of excuses about why they can't meet up or stay in contact. The simple truth is, if you like someone, you will pursue them in a sustained and consistent way. This is all the more true with men. If men want you, they are relentless. Once excuses start rolling in; you have sadly moved from their main focus to becoming an "option." This is the zone you don't want to be in. It's at this point that honesty and decisive action on your part is pivotal.
If you do not want to waste weeks or even months of wondering where your interaction is going, then you need to take control of the situation with decisive action. You have to let them know how you feel and mark out your standards. If you don't, you will remain an option that will most likely never reach fruition. However, if you respectfully assert your concerns, then you are at least in better stay to encourage them to make a decision, and hopefully a decision for you. And if not for you, then at least you don't need to waste your time on a time-waster. It is their right to be indecisive, but it's your right not to wait around and tolerate it!
This mode of action requires courage and confidence; two traits that will serve you well in any lasting relationship. Don't render your power to someone that views you as an option. Take control of your narrative. You are someone's number one! The longer you stay with an indecisive person, the less time you have connecting with the true one. So be bold and honest. Take control of your love life.
A wonderful quote that's worthy of full acceptance: "An honest answer is like a kiss on the lips."