Gani999 is right, an EU citizen doesn't have a time limit on their stay or need any type of visa, a non-EU spouse does.
I have been looking into Schengan visas so my husband and I can visit Greece. As a British Citizen I do not need any type of visa to travel to an EU country, though if staying a while think some countries ask you to register with the police as a resident (not sure if Greece is one of these).
My husband, as a citizen of a non-EU country requires a Schengen visa which will be valid for a maximum of 6 months from date of issue for single or multiple entries of a
maximum of 90 days in total. Don't think it is possible to get one that lasts for any longer. Good news is, it is free to spouses of EU citizens. You have to apply through the Greek Embassy in London and they operate an appointments service so you can't just turn up and get one stuck in your passport the same day. Think it takes a week or two to get an appointment and a further week or so to receive your passport back. Have to fill in an application form, take yours and your husbands passports, marriage certificate, etc. They have a website
http://www.greekembassy.org.uk, look in the consular section.
In regard to future children it would depend on their nationality, if they have British citizenship (?? - you don't say what country your husband is from) then as EU citizens they don't need a visa, if you apply for British citizenship in the future you also won't need to apply for visas every time you want to travel to Europe, and can live and work in any country in Europe with no restrictions.