Partner has very low sex drive.... HELP!

I have been with my now husband for almost 6 years. In the beginning of our relationship sex was never a problem. Now that time has passed, his libido has dropped very low. He was getting Testosterone shots but now longer wants to continue getting them. We are not necessarily TTC but we are also not preventing it. We no longer use any protection and I had my Mirena removed 5 months ago. Could he possibly actually be afraid that I might really get pregnant or is he just not in the mood like he says. I would really love to be more sexually active not only for TTC but for the health of our relationship. What are some things I can try to help boost his libido or what can I maybe discuss with him? All help is sincerely appreciated.

P.S. I really do want to get pregnant and hopes that it does actually happen and he knows this.