S.O. nervous (TMI)

My s.o. is 100% on board with trying.. but he is so nervous about babies.. he can't seem to get out of his own head when we are doing the baby dance.. so while we may be having plenty of sex during the right times it doesn't work if nothing is happening.. ts almost like stage fright ...anybody else been through this and if so any suggestions would be great.. it have tried not talking about making a baby so it's not in his mind but it seems that now that we are actively trying that's what he automatically associates sex with.. TIA