lintu,
Let me ask you this. When your husband passed, did you make any attempts to communicate with him. Did you ask him for help, or ask him to give you some sign that he was still there with you?
The reason I'm asking is that sometimes other spirits can use that as a doorway or avenue to form an attachment. They can act as the lost loved one, and form an attachment. Sometimes its with intent, other times its just out of a need for communication or companionship.
It could well be him, but I wouldn't simply assume so just because of the timing of the events. It was probably also a time in your life when you were emotionally weak, and as such susceptible to outside influences.
Remember, in death as in life there are all forms of people. Some who are vocal, intend only good and would never knowingly cause distress to someone. Then there are those who really are quiet, and can co-exist without anyone ever knowing they're around. They're there but you'll never know it. And then there are those with a purpose and they really do not care who or what gets in their way. They've lost sight of the concept of consequence (if they ever had it) and are pure drive.
Have you ever tried doing an EVP session?