These drugs may or may not help you. This sounds more like a valve issue. They are not covered by insurance normally, but you might try them and see.
Cialis is supposed to last a couple of days so they might give you more planning time. I have heard from others that Viagra stays with them for a day but does not take affect in 30 min for them.
I understand wives generally do not like to plan an occasion, so you will need to become extremely familiar with her cycle and behaviors. More communication will help.
It will take a prescription for these, which most doctors do not mind giving. There is only a slim chance of any bad side effect.
If it is a valve issue, you will need surgery to fix it.
Also, have your prostate tests done and eliminate any possible problems there.
Lastly, just because I let everyone know this, if you otherwise masturbate to porn, you need to remove your mind from this to be healthy in the bedroom.