There was this guy who loved two gals at the same time but he didn't know which one he loved more. Someone taught him.
Ask yourself this question and answer it honestly :
"When you are happy, which gal would you want to share your happiness with?" The one you think of is someone you love.
Ask yourself another question and answer it honestly :
"When you are sad, which gal you want to share your burden with?" The one you think of is also someone you love.
If you think of the same gal when you are happy & sad, that's the most perfect. But if you don't think of the same gal, I would advise you to chose the one you are willing to share your sadness with.
In life, there are more sorrows than happiness. There are too many people that u meet that u can share your happiness with, not necessary your lover.
If you live your life happily, you can also enjoy it alone.
In sadness, however, there are not many people willing to share your burden with you. If you are willing to tell someone your happiness, I am sure that person has got to be someone close & an understanding person to you.
But it shouldn't stop there. If that person only thinks of you when she is happy, but looks for someone else when she is sad, this lover is too unstable, she doesn't treat you as someone she can spend the rest of her life with.