A relationship involves two individuals who are bound together to some extent, by things they share in common. If there is nothing common about you two, then it is highly possible that you are just wasting your time and that you need to stop it all and move on with your individual lives.
If people are using you to satisfy their certain needs and do not care about your feelings, it is in the best interest that you step aside and leave.
It is true that the person you think you love can use you for selfish gains. They can even use you as a backup plan just in case.
Here is how you will know if you are just a mere backup plan for him/her:
1. You haven't met their family or friends
It could be true that the person you may think you are in love with is just using you and is disguised in a figure you know nothing about. They could as well be in another relationship and will want to keep you in the dark long enough until something happens which is when they will open up.
2. You force them to make commitment steps
If they are not into you and have nothing in common with you, they won't do anything to show commitment.
You will instead be reduced to begging and making them say or do anything that will make it look real. This is just like dating yourself or a kid whom you have to force to do anything.
It also means they could be committed elsewhere and they only have you around just in case something does not go according to plan on the other side.
3. They cancel plans all the time
People who do not value your time and behave like they have nothing to do with do not deserve your attention at all.
Cancellation of every plan you make just means they always have better people to spend time with and are only keeping you in the waiting just in case something happens.
4. They don't spend on you
If they love you, they will spare a few coins to surprise you even with petty gifts like airtime or foodstuff. If their money does not see sunlight in your presence then, trust me, you are a backup plan and they have better people to spend it on.
5. Things are done at their convenience, not yours
Everything you do and plan together has to be at their convenience and not at your convenience. If they do not have that time then, it will not happen but if they say it has to be done at a certain time, then, it will be done even if you will be busy.