you really get what I was saying: the fuck machine thing that really kills you after some weeks.
I go doggy because it's more confortable for both: we're not into the acrobatic or romace stage, we just need to do the job.
Sounds like an erotica killer to me.
In addition to the most important stuff (sufficient calories of sound nutrition, exercise, sleep, hydration, etc) I say oysters work for horny (probably has to do with zinc), as do eggs and fish. Without putting it too delicately - these foods go straight to my balls. Also, let your nuts hang. Tight underwear will keep them too close to your body which makes them too warm and less likely to produce viable sperm. Stay away from hot baths and steam rooms too.
Women are probably helped by similar general good health practices and I've heard that folic acid is a beneficial supplement. I'm sure her doctor has advised her about all this stuff.
If you're really desperate you could try some hcg. Pure horny juice, that stuff. Scary. Fertility docs probably have barrels of it 'round the back.
If you're tired already, it might be wise to get your sperm checked, and her.... whatever they do... That way you both know it's going to happen and don't have to have lingering doubts.
If she is near your age, I hope you have discussed what to do if the baby is less ideal than hoped for, and that you are both on the same page.
Generally, take a less mechanical perspective and get some psychological thrill back into it somehow. Use the 'job' that you have to do to explore one another's fantasy lives. Human's are endlessly fascinating when it comes to sexuality, so if it feels like you have reached a dead end it's only because one or both of you aren't open to communicating. If it feels like a chore, I'd examine why.
Genuine sexual arousal is probably important too. The male will ejaculate more forcefully and there are studies which indicate a female is more likely to conceive if she has orgasmed. [/Dr. Ruth]