Last of my lovers

I'm 63 and my husband died three years ago.Prior to meeting him,I had five serious relationships and,yes,slept with them all for quite lengthy periods (they were all at different times!).I've found out today that the last of them died in March.Talk about being depressed!I've been on my own since my husband died,my children live abroad and due to cancer,have been unable to get out much.On the mend now but hearing the news has really thrown me.All I seem to do is look back never forward.Any help or ideas to get me into a more positive frame of mind gratefully received.