Hey! So there could and are many answers to this question.
First, if one is feeling like the relationship is a chore and don't enjoy the other anymore that could be a sign that you should break things off.
Secondly, if you are always fighting about one thing or another and can't seem to agree about anything. It should be quite obvious that there are some problems.
Lastly, if the intimacy isn't there anymore and you don't enjoy being with your partner anymore that's another sign that you are probably losing feelings.
Hope I answered your question, let me know if you have any more questions!
