If you're behind on the bills, then, no, it's not a good idea to spend money on a vacation.
However, it seems you're both really close to burning out due to stress, so I would make it a priority to get some days off together to rest and spend time with each other at home doing things that don't cost money. I understand the desire to go somewhere else, but unless you can do that without spending money you don't have I wouldn't recommend that in your situation. Personally, in our family we have someone who lives close to us but not in an inner city environment but in the middle of nature. When that person is away on a trip, we like to spend the weekend at their place to get some rest and some change of scenery.