What Does Clear, Slimy Discharge After Having Sex During Periods Mean?

I started spotting on 2/13/11and stopped on 2/14/11 then started full stream on 2/15/11 and went heavy for 2 days that would put me to 2/17/11 then on the 18th light spotting and off by that afternoon. Had Sex with my husband the morning of the 19th, but while I was on my cycle I noticed that it looked like there was slime in the cycle, then when I went to the bath room to pee, when wiping I noticed there was clear, slimmy discharge coming out of me, this was something different for me I have been with my husband for 8 years and have 3 children. We are trying for another baby, I am also 42 yrs of age. I hope that you can give me an answer. Thank you Karen