Ok. Sorry to keep repeating myself but please keep doing this all month long even if you don't think it's necessary.
Has he ever had a sperm analysis done?
Re SMEP, if he can't DTD that often, then just do what he can do.
I can't tell you what is going wrong here. Some of the things you were doing in the past were not conducive to conception and it may be that we've made the right changes but the right sperm just hasn't met the right egg yet. Occasionally, though, when we've gone on a long time not getting pregnant, we've found that there was some male factor infertility or endometriosis/other physical issues preventing conception and so it may be time to consider having things checked out now.