My wife thinks I should see someone for my bruxism. Is it really necessary?

Yes, do it now. Most of us underestimate our own habits. She is observing something about your behavior that seems related to bruxing your teeth (or more commonly clenching your teeth). Vist an excellent bite dentist or TMJ dentist to get the fastest results. You will have less stress with your wife if you go ahead and make an appointment.
Depends. Bruxism is the name for grinding one's teeth, usually during sleep. This can cause erosion of tooth enamel, and it may be a symptom of other conditions or diseases. Check with your dentist and your family doctor.
Yes. Yes, at least evaluated to see how much of a problem it is. See TMJ expert. Any dentist can be a TMJ expert with the proper training and experience. Most commonly, oral surgeons, prosthodontists, and orofacial pain specialists. Ask your MD, your dentist and your dental society for referrals.
Yes. Bruxism may not be causing any discomfort at this particular time in your life, however the damage is being done. Muscles, joints and teeth are all involved. Pathological tooth wear can result in a myriad of future issues which may be very costly. An orthotic can prevent or retard the adverse effects of this habit.
Depends. Is it for during sleep or while awake? Daytime teeth clenching can be controlled by behavior modification; sleep bruxism can not. If your teeth are wearing and/or you have some facial or jaw pain, you should speak to your dentist about it.