Opk help

So i know how to tell a positive opk. I think my problem is we don't bd at the right time. I have seen male sperm can live for up to 5 days which is why fertile week is important. I start opks 2 days after af bc some months i ovulate early sometimes its late. I guess my question is say i dont bd till i get a positive will i be less likely to get my bfp? This month we are going to bd every other day trying for day before of and after positive opk. I am also on my 2nd round of clomid. Last month i thought my opk was positive. Then a week later had ovulation like cramps so tested. And there was no question it was positive. So we bd that night. Following morning was negative so i think i missed my window. Any insight our help is appreciated.