He needs to see a doctor.

Find lots of articles online about testosterone levels and print them out and leave them where he'll see them (when you're out).

Give him a couple of weeks.

Ask him (seriously) "will you see a doctor for me?" That's a yes or no answer. If it's yes, then YOU call and make the appointment.

If it's no, then you might want to think about a separation. You don't want him to think that you're not serious about this.

It's possible that this is a really simple fix...