He said he’d leave me no problem

My boyfriend told me without hesitation he’d leave me in a heartbeat if his ex reached out. That was very hurtful to hear and I’m trying to process how it’s making me feel. We’ve been together for about 9 months. Idk where his comment came from because exes weren’t even in conversation. Feels like a huge slap to my face, exes are exes for a reason…so to tell me that made me realize that he must not value me or our relationship after he pursued me first 😞