Can a men fall in love with other women after his marriage?

Your curiousity makes it sound like you're interested. Try not to worry about why he is feeling the way that he is. Love is not self-seeking, so if it was true love, he would not express this knowing that it messes with your head and interferes with your marraige. Ask him to stop expressing these things, save your marraige, and let him get over his feelings. They are just feelings - and they will come and go. You are not missing out on anything. Be true to your spouse and the committment you made.