SPOUSAL VISA USA HUSBAND UK WIFE

My wife is a UK citizen. I am from the USA. I want to be able to stay beyond the 3 month visa that is issued. We have been married a long time, are in our 60's, and retired. If you can answer any of these questions it is very appreciated.
Can the spousal visa be done online & about how long is the process?
Will I have the same privileges as my wife with this spousal visa?
When flying back to Europe can I enter from another country other than the UK with this visa and not be subject to the 3 month visa limit.
When departing Europe can I depart from another country other than the UK and not have a problem that I stayed beyond the 3 months?
Thanks very much

Where do you and your wife live now?

I can only ask some of your questions! Yes, you apply online and, from the US, decisions are usually made quite quickly. You can also apply for priority which will make it even quicker. However, there are requirements under which you can apply, financial, proof of relationship and accommodation. You will need to check the Home Office/ UKBA site to get details. You will have some privileges the same as your wife but there are also limitations. Again, check the NHS site to see what services you would be entitled to at the present time (things might change!) You would not be entitled to benefits until you have Indefinite Leave to Remain in five years time.