Have you charted your temperatures? Do you know when/if you normally ovulate, if you have a healthy LP, and if you have fertile mucous?
I'm sorry you're having a tough time getting pregnant.
No I havent as I dont really know what to look for. I believe its as the temp increases you ov? But if you bd after this have you missed the boat so to speak, as I thought its better to get the little dudes up there ready for the arrival of the egg?
Confusion is setting in

just so difficult TTC, how come there are so many unwanted pregnancies when we are trying so hard!!!
I can feel your frustration through your post.
Here is the overview of charting:
1.) Buy a digital basal thermometer. It doesn't need to be expensive.
2.) Take your temperature at the same time every day (right when you wake up, before you move around) and with the same method (oral or vaginal) each time.
3.) Plug your temperature into Fertility Friend (free).
4.) Note your cervical mucous and any results from OPKs.
5.) You will O on the day of your lowest temperature prior to three sustained high temperatures above your coverline. FF (Fertility Friend) will mark your ovulation date for you and your coverline for you a few days post-ovulation.
6.) If you maintain 18 high temperatures (above your coverline) post-ovulation, you are very likely pregnant.
So, that's just the quick and dirty. A good book with tons more information and details is
Taking Charge of Your Fertility; I recommend it, but there are also a lot of free resources online.
Basically, you would utilize all of your symptoms to determine your ovulation date, but temperature is the best way to know. After a month or two of charting, you will probably start to really learn your body, know when you will ovulate, what your usual symptoms are, etc. I know, who wants to wait that long? I would just start charting now and BD when you normally would, but pay attention to positive OPKs, your temperatures, CM, etc.
To give you an example of how it works for me, this past month I charted my temps and did OPKs starting on CD14 (I normally ovulate on CD16-17, but I use OPKs earlier just to make sure). I didn't get a positive on CD15 or 16, which was very unusual for me. My temps were still low, but I had no EWCM, so I figured I wasn't going to ovulate or it would be late. We were traveling, so I kept taking my temperature and noticed I started to get EWCM around CD17. We BD'd any time I had EWCM. I arrived back home on CD19 and took an OPK; it was positive. We BD'd because between the positive OPK, the ovulation pains I had, and the EWCM I had, I knew I was either ovulating right then or would be the next day. Lo and behold, on CD20, my temperature jumped 1 degree, so I figured I had ovulated on CD19. My temperatures on CD20-24 confirmed that I did in fact ovulate on CD19 because the temperatures on CD20-24 remained high.
All said, I did use a few different things to determine my O timeframe and when to BD, but ultimately, my temperature pin-pointed the exact date. The O date is only determined after the fact (because your temperature will spike post-O), so you do need to utilize
all factors to help determine when to BD. Again, if you have a "normal" cycle, you will probably start to know when you're going to O or what your normal is and you can BD at more accurate timeframes.
I hope that helps.

I am an avid charter and I really believe it helps people see a clearer picture of what is happening. It also helps to show if there are any issues (luteal phase defect, anovulation, etc.).