What's so bad about staying with someone until someone better comes along? Does "stringing someone along" really make you a bad person?

I know a lot of people who have done this, although I have never done it myself and I've never been a victim of it. I haven't done it myself because I think it's a waste of time to date someone I'm not REALLY into.

But my cousin did it.. she dated a guy who loved her for 4 years although she was not in love. She was always looking for better and one day she did find better. And as soon as the better guy proposed to her she broke up with her boyfriend of 4 years and married the new guy. They've been happily married with kids for years.

My brother also did this... he stayed with a girl for years waiting for someone better to come along and continued dating and seeing other people while he was with his girlfriend. After 6 years he found that he couldn't find better and ended up marrying her. She's not the love of his life, but he said he's just happy because she is happy that they finally married. So what's so bad about this situation if ultimately she got what she wanted - a marriage - and now they're trying to have babies. Double bonus for her for sticking around.

My sister did this too... and so did Taylor swift with Calvin Harris. She stayed with Calvin until someone way better came along - Tom Hiddleston. She'll probably end up marrying him. The two seem super happy together.

So I always thought this was really bad and selfish. And I have turned guys down who tried to break up with other girls for me. As soon as I find out there's a girlfriend I end it.. no ifs or buts. To me, a guy telling me "I"ll leave her for you" is a HUGE red flag...

but how come to others it is not? Have I been wrong to think this way? Does "stringing someone along" really make you a bad person?

What has been your experience with this and what do you think?
What's so bad about staying with someone until someone better comes along? Does "stringing someone along" really make you a bad person?
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