Denise, you've gotten several good suggestions on how to solve this problem so I'm going to offer an opinion on his behavior based on a similar situation I'm familar with. He can't stand not knowing whether or not he's been replaced by another man, and these daily contacts (for no apparent reason) are his way of knowing the answer.
In a similar situation, a lady I worked with got caller ID and timed it so that a coworker (a man not known by the ex) was there to answer the phone several times. The ex, without even asking the question, immediately assumed she was having a relationship and she did not deny or discourage his thinking. Her ex, like yours, had left her for another woman but didn't want her to have the same priviledge. By the third or fourth call the pretend boyfriend started telling the ex not to call and on one occasion implied she couldn't talk because she was ... well, ok I won't go there but you can use your imagination. I don't know if this scenario is possible in your case but in my coworker's situation, it drove the ex crazy and did eventually stop the calls and unannounced visits. In reading your post (below) her feelings were much the same as yours;
"I am still trying to 'get over' this and his calling me and finding excuses to come over only makes it worse."
and she got a measure of sweet revenge caused by his imagining her being intimate with another guy. It took only a short time for this harassment to stop. Whatever you do, take steps to solve this because he will continue to exert a measure of control as long as he knows you will be concerned with his involvement.
Best wishes and my hope for a quick resolution to this painful situation.