Intimacy problems

I've made the decision to wait until marriage to have sex so my bf and I are limiting ourselves to oral sex. For some reason he can't ejaculate or orgasm. I've tried several different things and I know he's trying as well. I asked him if he wants to see a doctor but he's way too embarrassed I'm just looking for advice on helping him in any way I can. Were both becoming rather frustrated and we appreciate any info you can give us. Thanks.