Parents of teenage daughters, please advice needed!

I caught 16 yr old daughter sneaking out. She was going to the neighbors, her friend from school that she said was her best friend at 1 am. We grounded her and went through her phone and she has been having intercourse with him, and been sneaking out for months. We grounded her for a month no phone, no nothing.

Punishment is over and her birthday is coming up. We are planning a package at an arcade place. She told me today if she could please invite him and that he is really important to her! I said probably not and I'd discuss with her father.

She was upset and looked depressed and teared up. I'm so worried she will start running away to be with him if I keep them apart. He doesn't even want to be in a relationship with her because he said he has commitment issues 🙄

I can't stand the sight of him. I'm disgusted because I feel he's using her for you know what. I don't want her to be heartbroken. I don't know what to do. A teenage girl who's in love with a user 😭

What would you tell your teenager? Any advice is appreciated. TIA. Sincerely, a hurt momma.