Low Testosterone

So I dunno where to write this...

My question is, do any of you women have experience with your hubby, S/O, fiancé, boyfriend, whatever your man is to you, having low testosterone?

What did you do to treat it? Did it effect fertility? What symptoms did they have when diagnosed? Did they improve?

Hubby confided in me he thinks he is struggling with this. He has a much lower sex drive, lower energy, loss of interest in hobbies he once had and so forth. He is in his mid 30’s.

We are pregnant with our third but wanted one more kid and I have heard from one person treatment can effect fertility and my hubby doesn’t want to take chances with that.