boy friends vs boyfriends

I have a neighbor who just moved here recently so he doesn't have many friends & he's always asking me if I want to hang out. I want to but I always have a bad feeling about it because I have a boyfriend. I know we'd just be hanging out as friends, but my boyfriend may not necessarily see it that way. I want to talk to him about it but there's been this tension between us & I don't wanna make it worse. If it's a bad idea to hang out with him, then suggestions on how to keep blowing him off? because I'm running out of excuses :(