Having trouble going on walks

Since being dumped in late January I find it difficult to go on walks. Every time I take a stroll around my neighborhood I am reminded of my ex. We went on quite a few walks when we were together, but of course I had gone on many a walk before him. Yet it seems memories of him has tainted this mundane action. I have been very sedentary since the breakup, I want to get out more, exercise more, see the sun. But whenever I'm just walking by myself I break down in tears.