Sex frequency during fertile week issue.

Im 34 and my husband is 38. We normally have sex once a week on a specific day ... He has lower libido then I do. I've communicated to him that it's very important for us to up our sex frequency to maximize our chances to conceive. He says that every other day for him during my fertile week is a stretch - he cannot produce big enough "load".  But he desparetly wants a baby too...