Welcome to the board! First of all, six months of trying doesn't mean that something is wrong with you. It takes the average healthy couple six to eight months to conceive being that each month you only have a 25% chance of conceiving. I would be worried too, if I were you though, since you did conceive other child by accident. Congrats on already having one, by the way!!
As far as the EWCM thing... I know that if you aren't doing the BD when you are having the EWCM, then you could be experiencing problems getting the sperm up there to the egg by the time you O. I would suggest, unless you have already tried this, do the BD the few days before you O, when you are experiencing the EWCM and then when it is time to O, there should be plenty little guys up there just waiting on the egg. I have read that it is far more important to pay attention to the CM for fertility than it is to pay attention to those OPKs. Don't get me wrong, I do like them, but I know that Fertility Awareness people do not like them for the very reason that you are complaining about. Hope that I have been helpful.
Just to reassure you... DH and I have been trying for fourteen months to conceive #2. We tried for eight months to conceive our DD. I am now on cd 32 awaiting AF because I my temp dipped a little this morning. I am still praying for a miracle.
Stay positive and try what I said for next month!!