Hi I Am Trying To Have A Baby With My

Hi I am trying to have a baby with my wife so latley we have been making love neally every night but sometimes when I go to sleep at night I have a wet dream and I wake up all wet but I don't have any sexural dreams and I'm not horny at all infact I get really angry because Its a waste of cum to me because where trying for a baby so if I knew I was going to have a wet dream I would of had sex with my wife instead. And when I wake up my penis is down. What is wrong with me? And how can I make it stop?