boyfriend going back to college and major anxiety

I need help ladies. im 20 and my boyfriend is 22. he is talking ab wanting to go back to college and get his degree and im so so proud of him !! BUT my good ole anxiety pal kicked the door open and was like "hold up. he's gonna meet so many new females and could possibly leave you for one of them"... any suggestions on how to deal w this without letting him know im anxious ab it bc i dont want to discourage him 🥺