If you do not know what it means to bear with someone, supporting them and seeking to help them and help carry their burden, even when their issues or problems or weaknesses are personally costly to you and get in the way of what you want, then you do not understand what it is to love someone.
It is not enough to simply withhold your wrath and keep your mouth shut while you seethe inside in frustration, as if the other person cannot sense it! And love is certainly not tapping your foot waiting for the other person to fix themselves to your liking else you will decide to abandon them.
To love someone doesn't mean that you never get frustrated with how their issues inconvenience or burden you. It means that you bear with them and even offer to truly help them get to a better place or help you both (relationally) get to a better place.
To love someone also doesn't mean that you enable people by sticking with them so that they can continue in their self-destructive paths without change. Love means that you sacrifice yourself for the good of the other person. If you have never truly asked, "How can I really help them?" and done something about it, even when it cost you, you don't really know what love is. Sometimes it may mean to stop enabling someone. Many times it means to start being there for someone and stop dumping them for inconveniencing you or "robbing" you of what you want.
Love, real love, will always cost in the long run. Love is the opposite of the common consumer mindset toward relationships: if you give me what I want and help me feel the way about myself that I want, I will stay; if you do not give me what I want, I will get it from someone else. People are not products or services.