It is tough to have to see someone you care about that doesn't show you the same level of feelings. In this case as he told you how he feels somewhat bluntly, it would be best to put the prospects of being with him behind you. Just play it cool: fake it until you make it. As long as you have a civil relationship for your kids' sake, that is most important. Try occupying yourself with someone you are excited about, like a hobby or traveling, or going to see concerts, exercising, etc. Throw yourself into some fun things so your happiness is not wrapped up in him.