I totally agree with SoMoMom. If your baby is still nursing, it is important for him to continue to nurse at night while he is still so young. I think the sleeping through the night is the biggest babyhood myth ever. Sleeping through the night is not the norm during the first 12 months. (My brother and sister were 20 months apart. They both had allergies. They slept through the night for the first time when they were 4 and 5 years old. That’s an extreme case though - and they slept in their own beds, too.)
If you have no problem sharing your bed with your baby, there is no reason why you shouldn’t comtinue to do so. If it maximizes everyone’s sleep, what’s the problem?
My son is 5.5 months old. He and I have slept in the same bed since he was 3 days old. We both sleep better that way. When he half-wakes to nurse (and he does at least once a night), I just scoot closer to him and he nurses for a few minutes and drifts back into a deeper sleep. He rarely fully wakes before 6:30am. Co-sleeping = more sleep for us both. Also, since I have had a problem with my milk supply since I’ve returned to work, the night nursing really has helped bring my supply back up.
I am also a single mom, so I have no one to help me with him at night. If he is up all night, I am up all night with him alone. I’m sure your wife is thankful to have a spouse who helps her at night, and lets her sleep some too. I totally understand what it’s like to be sleep deprived., especially since my son has been up practically all night for the past 2 nights with a cold/possibly an ear infection.
You could also bring his crib into your room so you don’t have to traverse the stairs if you’d rather he sleep in his crib.
Crying it out does work for some people. I have heard of people limiting the time a baby cries and gradually increasing the time. But I wouldn’t let the baby become hysterical. And if it isn’t working for you, stop and reevaluate. Crying it out would not work for my son. I would never attempt it. When my son cries, he does not cry alone.
A baby cries at night because he needs something. Whether it is because he is hungry or just lonely, it is still a valid need. If your spouse is lonely and needs to be close to you, do you push her away?
Babies are small for such a short time. He won’t be in your bed/room forever, if you decide to go that route. Follow his lead. Do what works for your family. Don’t let anyone pressure you into doing something that makes you uncomfortable.
Good luck, 
h_thur