Different people have different reasons to stay single. Most people's perception of being alone is to enjoy their life on their terms. There are many liberties of being single, and the most important one is sex. It's not that you don't get sex in a relationship, but the relationship obligation won't allow you to look for sex beyond your partner.
If you are living a single life just because of multiple sex partners (MSP) , then you are mistaken. It seems that you have not set your priority right. Many people chose to be single to fill their passion in life. If you dreamt of traveling solo then you shall have to be alone to experience your solo trip. It will help you if you know things before you develop promiscuous behavior. The fun part you pretty much know, but there are disadvantages also.
Your health will be the one that will suffer the most.
The number of sex partners increases the risk of sexually transmitted diseases. You can't ignore the risk of STDs because some conditions of STDs are still not treatable. When you have multiple sexual partners, having sex without condoms is not a good idea. Sex without condoms, in general, is also risky because of pregnancy factors. If you are not looking to start a family soon, it is better to have sex with condoms. Poor sex health is also associated with the number of sex partners. Your longevity might get hurt. Promiscuity also impacts your physical health. It would be best to avoid MSP and also inculcate condoms in your sex life.
The chances of sex addiction are higher with promiscuous behavior.
Sex addiction is real. You should know that there are risks associated with sex addiction. With sex always in your mind, you can't keep a happy relationship. To gratify your sexual need you might start looking for sex beyond your relationships. It would be best if you avoid things like pornography or such things that motivate you to gratify your sex needs from multiple sex partners. When partners find out about infidelity, they feel betrayed. Addiction also leads to another addiction. This one crucial negative is not suitable for your life.
There are psychological effects of multiple sex partners.
One of the research was carried out on multiple sex partners to find out the possibility of anxiety, depression, and substance dependency. Male and Female from 18 to 32 years of age participated in this research. There were age groups of three age periods (18–20, 21–25, and 26–32 years). The mental conditions like anxiety and depression have no significant association with the number of sex partners. But, the number of sex partners does increase the risk of substance dependency in all three age periods. If you correlate these two findings, you shall find a relationship because one of the research says there is a connection between depression and substance abuse.
People get into substance dependency because of depression. If you don't want any mental conditions to disrupt your mental peace, it would be best if you prefer not to be adventurous in the relationship. Sex therapy with a sex doctor shall help you in getting rid of any sex-related issues. The choice is yours.