erection performance

For younger men, two things come easy: erections, and orgasm. As you get older, these two facts of life, which you've taken for granted for a long time, ever so gradually become more difficult to attain. Sometime in the late 20s or early 30s, sexual desire and ability starts to slow down.
Fortunately, there is something you can do about it. The two problems each have their solution, and solving both together is best.

Well when i met my husband we made love and it was great, but now he's never in the mood. When he is, his performance is off. He is 30 and i'm 38. He'll be in the mood and all of a sudden he goes soft... 
See i love to have sex with him but sometimes we do it only twice in a month, some times less.
What can i do to help him because he feel bad when it happens to him. Can you help me to make his sex drive stronger please...