@match = /X\d.+?(?=X\d|$)/g;


##</code><code>##

    $_ = "X1aaX2bbX3heeX4...X5loveUX6XXXX7X8" ;

    my @match = split /(X\d)/;

    print "String: " . $_;
    foreach my $word (@match){
        print $word;
        print "\n" unless $word =~ /X\d/;
    }