Lisa, if the goal is to stop it, then there are a few things you can do, as you have the absolute right to have it stopped.
This may give you some help:
If you have come seeking assistance for a paranormal problem, we're here to help. This thread is the PNF Approved Intervention Methods for many of the events we hear about often. Although many of our members will give you their personal advice and methods, we want you to have the basics that...
paranormalforum.net
One of the things I talk about on that link is to lay out boundaries.
Speak out loud to the visitors and tell them you no longer wish to see them, they are no longer allowed to appear, touch, speak to you, or to follow you. And say this firmly and mean it. Repeat as necessary and refuse to acknowledge them other than repeating your boundary statements.
Second is to pray the St. Michael's prayer daily. This is a prayer of protection that works and is used by many faiths. It is in that link for you.
I am also going to add that you should continue to see any mental health provider you have been working with. Your grief may have opened a doorway, and the best way to close it is to work through the grief process with help. Losing a loved one, especially a husband, is a huge shock to the system to begin with. Also, science is finding we may have an "energy"/psychic connection to each other and it sounds like the two of you may still be tied by that connection.
Those that have passed should not be here on this side of the veil. It is no longer their place or home. They need to move on.