Boyfriend can't perform in bed, need advice!

Hi there,

I'm 32 my boyfriend is 37. I've been with my boyfriend for 9 months, we love each very much. We've been trying to have sex for 6 months now. Everytime we have tried, he's hasn't been able to ejaculate. The only time he's able to ejaculate is when he's masturbating on his own to either to porn or to images in his mind. I've tried toys, didn't work. He went to the doctor and got Cialis, which helped him stay hard longer but never came. I've dressed up, told him to cut down his masturbating from everyday to half as much. The week before we were together he masturbated just once. Still couldn't come. I suggested we go to a sex therapist but he's adamant about not going. I can't force him to do something he doesn't want to do. He's had this issue in the past with women, not all of them just a few and says it's because there's no passion. In the beginning when this problem started he said it's because he's old (umm no I don't think so), then he was saying he was thinking too much about performing and now he's saying there's no passion. I feel like something is missing. He says he loves me, I'm beautiful but feels like there's a lack of passion which is why he can't perform. He's only been with 5 or 6 women in his life about once or twice each so he's fairly inexperienced compared to myself. I asked if my experience intimidates him and he honestly said no. We are fantastic in every other aspect of the relationship. Any thoughts?