My hubby had "suboptimal sperm". we were going to start intrauterine insemination before moving onto IVF but then I got pregnant on clomid during the workup phase.  A clinic can do a sperm washing and pick out healthy looking sperm to inseminate into you.  Its a bit of a process and you may need to go on hormone injections to increase you chances.

sperm quality can be reduced by smoking, alcohol, unhealthy diet, obesity, medication, exposure to heat or chemicals.  Some jobs can create an occupation "sperm" hazard.  Encourage hubby to keep healthy, loose, breathable underwear and stay away from chemicals.  He sounds like he is already doing most of what he can to increase his sperm quality.  Try not to push it too much- infertility can be VERY stressful on a relationship.  I will add a link to my advice on infertility.

good luck to you and your baby making attempts.

BTW- I now have twins, 4 years old and a 9 month old- so we had success!