Sexual Relationships 
Sexual Health 
This is not a list of reasons, there is no number 1, number 2, number 3, etc. These are my opinions, and they should not be taken as a fact.
Some people go into a friends with benefits relationship thinking they will not get emotionally attached, because they agreed it would be just for fun. However, one of the people may get emotionally attached and want something more and by the time they realize it, it's already too late and they are hurt.
The other sex partner may not realize it but the other person is heartbroken because they see that the other partner wants sex and they take that as a sign they don't want a relationship.
Even though the person may have agreed to it to begin with they may feel used. Speaking of sex, one of the friends with benefits partners may start to wonder if they are having sex with someone else while they are friends with benefits with them.
The person, after having sex may not even feel like they are friends with the person anymore. One of the partners may become insecure if they know their sex partner is talking to someone else which could lead to paranoia,jealousy, possessiveness, resentment, or anger.
There is a lack of self respect because in a way, the man or woman is allowing their partner to use them for sex. It could potentially be awkward or embarrassing for the man or woman who initiates sex because they could get told by their partner that they no longer want to be friends with benefits.
The ego may be hurt but if the person falls in love he or she could be hurt once they find out the person has moved on in the relationship.
The argument I hear the most is that friends with benefits is different from fuck buddies, because you are not having sex with a complete stranger. The friends with benefits may not be a stranger, but if you allow a person to have sex with you he/she may only contact you just for sex.
If you use to hang out and talk about things with your friends with benefits he or she may not want to do those things after you start having sex with them. Also, people do change over time no matter how well you know them.
My final reason why I think some people should not be friends with benefits is because of stds. Your sex partner could have caught something from someone else. They know they are not exclusive and maybe they sleep around, when you were friends you did not know his sex lifestyle.
What Girls & Guys Said
1 1Nicely written take.
Thanks
I think friends with benefits is just wrong...
Why do you think that?
Being a Christian, I feel one should only have sex with their spouse. (And not marry for the sake of sex...)