He walks outside the bar, looking around. He often goes out to drink, and it just makes him think that he's losing you, his lover.

Anywhere he goes when he's drunk, he thinks you're right there, cheating. Due to the previous events with his ex, he got scared of losing someone he loves.

So he's calling you, hoping that you'd pick up the call. When you do, you always ask:

"Why'd you only ever phone when you're high?"

Now you have to bring him home again.