How do I get my 8 yr son to get out of his infatuation phase with my neighbor's daughter. I want him to focus on his studies only!

Kids grow up fast and the changes in them are faster! Instead of getting annoyed or angry you need to talk to him. Talk about your childhood and tell him how you also had a crush and then eventually it went away. Tell him its normal to have crushes but one shouldn't lose focus. Engage him more in sports or other activities. This is just a phase of growing up!