He never asked about your private life
No matter you meet at his house or your house, you will definitely have some communication. The content of your communication can be used as an important basis to judge whether this is a romantic or causal relationship. A person who is sincere to you and wants to further develop with you will seize every opportunity to learn more about you. Only in this way can he be sure that you are the one he really wants. In addition, he will try his best to let you know more about him. But if he doesn't have any interest in your personal life, it means he just wants to keep your secret benefits relationship at a casual stage. He doesn't want to know you too much because it increases the risk he will face. Only when you have fewer connections can he ensure that the relationship is simpler. In this way, it will be easier for him to end the relationship. So when your partner rarely asks about your private life, you should reconsider whether you want to continue the relationship.
Leave as soon as sex is over
For those who have fallen in love with their sexual partners, this is very cruel. They long for a romantic and sincere dating relationship, but what they get is a casual relationship. But it's good for you to understand the nature of the relationship as early as possible. If your friend comes to your house just for sex and at the end of sex, I leave you without hesitation. There is no doubt that he regards you as his FWB. If you can accept the relationship, or think it's good for you, then you can continue to stick to the relationship. But if you think the relationship will hurt you, you should stop it immediately.
You find him dating someone else
As we all know, a serious dating relationship is exclusive and belongs to two people. If one of them is running a committed relationship and dating another person at the same time, that person will receive moral condemnation. However, in a NSA relationship, it is perfectly acceptable to have multiple sexual partners at the same time. So if your friend just treats you as a FWB, he can inadvertently mention that he is developing this relationship with another girl.