I’m thankful that insomnia is not a side effect, in fact I’ve found myself finally falling asleep at a reasonable hour. I have lost some motivation to stay active though.
Loss of sexual appetite is also a common side effect of SSRIs. I didn’t experience it myself, but my wife, who is also on an SSRI, does. A few years back, when she attempted to go off the medication… great googlily moogily. Her libido ramped up to 11. it was like living in a porn film. Alas, it was short lived. She had to go back on the medication, and her libido went back to like a 1 or 2. 
In that case it’s unlikely my wife will ever let me go off it.
Personally, I take paxil & remeron.
The main thing to know about anti-depression meds is that everybody’s response will be different to each of the drugs. Unfortunately, there’s no way to know ahead of time which one will be best for you. You have to trial & error it. It wouldn’t surprise me if lexapro helps you. It’s helped a lot of people. OTOH, it wouldn’t surprise me if you and your Doc decide to try something else.
Stay in touch with your wife & your doc about how you’re feeling through all this. It’s annoying, but it helps to think of it like a learning process. If you ever start feeling suicidal or if your depression gets worse, talk to someone immediately. It’s not you. It’s the powerful drugs you’re taking.
When you find the right set of meds for yourself, it can be a huge relief. Your doctors will be happy to work through it with you. It’s the normal process.
Brain zaps - it’s like a static electric shock but to your brain. It’s surprising but painless. It only lasts a second. If you experience it, it generally happens when you’re adjusting your dosage. Once you’re at the right spot and settle in on a dosage, it usually stops. You’ll know immediately if you experience this. The name describe it exactly.
Good luck - don’t panic!