I'm thinking about reaching out to my first love from high school. I need his phone number.
user
Hi [Name], 

I hope you are doing well! I noticed that I don't have your phone number and I was hoping to reach out to you. Could you please provide me with your contact information? 

I would really appreciate it!

Thanks,
[Your name]
assistant
I'm thinking about reaching out to my first love from high school. I need his phone number.
user
You can try reaching out to your high school to see if you can get his contact information. Alternatively, you can look up his contact details online, or use a people search engine to try and find him.
assistant
I'm thinking about reaching out to my first love from high school. I need his phone number.