Trying but he is in the mood sporadically.

Me and my wonderful bf are trying. Have been since we started dating, we both have been step parents and never a parent. He has been divorced twice, his most recent of several years, and she and him didn't have sex very often the last few years. I am divorced once, and widowed once.. He has PTSD from war, and I have it from rape. I, originally, thought that this would make us closer sexually. My late husband helped me work through some of my sexual issues. However, when it comes to sex he has a hard time getting it up, and then an even harder time getting off. we have sex about once a month right now. Like I said, we are trying to get pregnant. Since we are only having sex about once a month, it's with no luck. this is making his depression worse, which is making his "problem" worse. He wont go an antidepressants, because he doesn't think he needs them. I am beyond sexually frusyrated, and stressed. I don't know anymore tricks or tips to help him feel better about things. I feel I should also mention I am working on a psych degree, and work in that feild already. I am reaching out, mostly for support, and any solutions. Leaving him is not an option! So please don't say it. I love this man completely, even if we never conceive naturally, or at all. We haven't looked into anything else, because of finances, yet. Please you support, and tips will help.