Encouragement please 😞😞

I am 20 years old I have been in three relationships in my life. All were guys and I’m still a Virgin meaning I didn’t have sex with neither one of them. None of the relationships lasted more than three months. And they all ended the same way. Honestly I’m embarrassed because I’m currently single. I feel like I don’t deserve to have a happy relationship. I think I may have developed low self esteem