I also agree with what all have said. Libido went to nill when I tried some of the medications out there to help with depression.
Now that I have stopped taking any type of medication, libido is good but still inconsistent due to how I am feeling while dealing with PTSD. My partner and I sometimes make love a few times in one week then nothing for two weeks if any of my triggers are active or I am feeling stressed to the max. Bless her for being understanding.
As others have suggested, talk to him, I know that it helped when my partner and I spoke about it. She now understands that it has nothing to do with her, just that when I am stressed or anxiety ridden, making love is the last thing on my mind.
I know that she would like it more frequently or at least more regularly, but she understands when I "don't feel in the mood". Since she is so wonderful and important to me, when I am on my game, I try to make romance a priority.
Maybe your partner needs to hear what you have to say, as I didn't know how it was affecting mine until we chatted about it and she told me how she felt. After our conversation I knew that I needed to make romance a priority for her and for us when I am having a good day.
Just remember though that I am now off all meds. I know that I wouldn't have been able to resolve the issue while on meds as side effects such as lack of libido really knocked me on my ass.
Hope this helps.
Good luck.