How can I add my husband to the property title & what are the disadvantages of adding him?

Adding someone as a co-owner of property is simple -- just execute a quit-claim or grant, bargain, and sale deed from you to you AND him.  As to whether you want to do so, that is another question -- it would appear to constitute a "transmutation" of the property -- essentially a gift of half the equity, which may not be the result you will want to be true now, or sometime in the future.  See http://www.willicklawgroup.com/property-rights-and-division/.  If you are at all unsure of what you are doing or why, seek out the advice of a family law specialist before signing anything.