Because I can't increase mine

I am 41 and he is 43.  I have been waiting for the so called increase since I was 38.  I really was anticpating it.  I have a 18 year old from my previous marriage, a two year old from this one and I just found out that I am expecting again.  After I had my two year old I had the Mirena IUD placed, it wasn't all it was cracked up to be mood swings, no sex drive, etc.  I had it removed in June 07 and yes I got my drive back, but it still wasn't as strong has his.  It never has been and I guess it never will.  I tried prescribed hormone therapy "Estratest" , Avlamil, even anti-depressants to make sure I wasn't depressed.   . . . .  So now it is his turn.  Do medications effect his testosterone level?  Help please.