Your husband's problems does seem like erectile dysfunction
.There can be many causes for this hormonal,systemic illnesses like MS,diabetes
etc,drugs,psychological problems,neurogenic disorders etc.The main cause has to be identified for the effective treatment.I suggest that you husband and you should see a specialist like a sexologist
who can help in counselling
him and also try to figure out the underlying problem.Only can then there be some change.I suggest he talk to a professional,in case he's embarrassed to talk about this with you.