sex every night on my fertile windows before and after also! need more advice ladies.

Me and my husband have been trying to conceive for a couple of years now we have a four year old daughter I need more advice on how to do this we have tried pre-seed and nothing!!! we try to have sex after I get off my period every night until I start my period again I log EVERYTHING I don't miss a log we go by the APP I take a ovulation test and when I see its at its highest peak we have sex at least twice that night I also take prenatal vitamins because they say they help to conceive as well I don't know what we are doing wrong I need help or more advice there was a point where we quit trying quit talking about it just let it go and maybe a year later started trying again