How can I help my long-distance boyfriend destress?

My boyfriend and I live about two hours away from each other, so since I’m a student and he has a job, we see each other every other week or so. We get along perfectly when we’re together and I have absolutely no doubts about the relationship (we’re moving in together in September), but when we’re apart, things get stressful. We’re both less secure when we’re away from each other and more stressed in general about our lives.

He worries a lot about debt, and gets stressed out about his credit card debt, so he calls me to vent. I often feel guilty when he does, because I know he (completely willingly; I try to talk him out of it) spends a lot of money seeing me.

I don’t know how to comfort him or just listen to him when we’re talking on the phone. Because I can’t hug him or distract him with something fun as if we were together, I feel like I need to fix his problems (which is impossible and not what he wants). It’s gotten to the point that I’ve started to mildly dread talking on the phone with him.

Summary: My long distance boyfriend gets stressed and needs to vent, but I don’t know how to listen and provide comfort and support for him when we’re talking on the phone, so I panic and get emotional, and things spiral from there.