Seroquel is an atypical anti-psychotic and is what is helping you rest and keeping the mania at bay. Celexa on the other hand is a very good SSRI (Selective Serotonin Reuptake Inhibitor) and is also sold under the name Lexapro. Serotonin is one of the neurotransmitters in our brain, a signal sent from brain cell to another. It is secreted by a portion of the cell called the synapse and it is effective as long as it remains in the brain chemistry before it is taken up into another brain cell. By having the Serotonin floating around longer, it leaves you with the "all-is-well, warm-fuzzy" feeling more than you would have without the SSRI. It will also have a bit of a sleepy effect on you. When you have two or more drugs that create the same side effect, it is known as a symbiotic additive relationship where 1 + 1 doesn't necessarily = 2 as far as the effect but 1 + 1 may = 4 so until you are familiar with the side effects, taking them on an empty stomach, relationship of dosage time to driving time; DONT DRIVE. YOU ARE RISKING A DUI.
The only thing about your medication regime that concerns me is that you are not on a mood stabilizer. The seroquel will make the mania not so bad and the celexa will make the depression not so bad but it would be great to see you stabilize and not have to bounce between moods. Lamictal (generic lamotrigine) is very effective and works well for a lot of people but some of the other common ones are depakote, topamax and lithium salts.
May I recommend that you and your wife look up the local chapter of NAMI? They have free education programs that are excellent that are designed separately for the patient and the family member. There is a direct correlation between the more you and your family educate yourself on your disorder, the more likely you are to find a plan of recovery that will work for you and your family. Recovery is possible and in some situations, couples find strength in this adversity and grow closer than they ever thought was possible. If you ever have any questions, do not hesitate to ask, myself or anyone here.
God Speed and Best Wishes
ptk