In life, there are those relationships where you really love someone, but they're just not right for you and there's a little bittersweet feel to it.

This quote is referring to romantic relationships. It means that sometimes you may care deeply for someone and have strong feelings for them, but the relationship is not right for either of you. Even though you have strong feelings for them, you must still acknowledge that the relationship is not going to work out and this can be a sad thing to accept.