I agree that it is highly likely that the loss of sensations is due to your husband's medications. And it would be a good idea for him to speak with his doctor with regard to changing the antidepressants if this is possible.
There may also be another underlying cause and it may be worth getting blood tests done to rule out other illnesses like glucose intolerance or diabetes than can cause nerve damage and loss of sensations.
It may also be a good idea to get counselling therapy for his depression if he has not had an opportunity to have counselling. Sometimes there is a deep routed cause that needs to be tackled and dealt with for the person with depression to try and come to terms with this and help to come through this depression. Going for walks in the fresh air, doing things that he likes, exercise, relaxation, avoiding stressful situations as well as a healthy and well balanced diet will all help.
Of course, if he is very low he will not want to do any of these things, but it is important for him to at least try. His doctor may refer him to a specialist counsellor to help him deal with the depression.
Best wishes.
Taking things like Viagra will not help with his problem since he has the ability to get an erection.
You and your husband need to talk to the doctor who is prescribing his depression medication, since this often is the cause of his problem. There are many alternative medications available, so why take something with a side effect that is affecting him and your marriage?
If you get no results with this doctor, get a 2nd opinion. Also research this medication online (drugs.com is a good place to start), and if you have to show the doctor the side effects at a visit, do so.
If all this fails, then he may want to see an Endocrinologist to see if he has a hormonal imbalance. But my guess is his depression medication is causing the problem, which is very common (esp. if he is at a very high dose).
Most likely the depression and the meds are the cause.
Boost the levels of erection-building nitric oxide
One of the biggest threats to sexual function in men is a breakdown of nitric oxide, a natural molecule that enlarges your blood vessels, increasing blood flow throughout the body, including to the penis. But as you get older, your body starts to break down nitric oxide much faster, making an erection harder to achieve and even more difficult to maintain.
One reason that Viagra works is that it slows the breakdown of nitric oxide, allowing for better blood flow. But the fact is, there are other natural ways to achieve the same result.
Our bodies produce nitric oxide from an amino acid called L-arginine, which is is easy to find in supplement form-and much less expensive than Viagra. try 3,000 to 5,000 mg daily for three to four weeks.
Also try rhodiola rosea. Like most adaptogens, rhodiola can regulate your hormones, increase your energy, improve your mood, and heighten your sexual desire as a result.
It's safe to take even while you're on other drugs, but don't stop taking it too quickly. Wean yourself off gradually or it can cause some mild withdrawal symptoms.
Talk to his doctor first and ask if it's OK to try these.