NOTHING!!!.....YOU ARE DREAMING!!
It could mean a lot of things. A few times in my marriage I have had 'thoughts' about my ex-wife. I realized that whether we could continue as husband and wife (we couldn't) or not there were extremely strong feelings between us at some point and those feelings don't ever fade completely unless the marriage is ended due to horrific violence, etc. which wipes away any positive feelings you may have once had.