How have you involved your family? Have you done any education on what OCD is in general and the specifics of how it affects you? Have you gone to your therapist with other people? Have any of your family members been to an OCD support group or other similar group?
Have you talked about ways in which your family and other important people in your life can help you with OCD instead of facilitating or enabling it?
I had my wife go with me once to my therapist. It wasn't incredibly successful, mostly because my wife didn't feel the same connection and ability to open up with my therapist like I do. It kept our conversation at too much of a superficial and non-specific level.
I have since talked to my wife about my various OCD themes and many of my specific OCD-inspired anxieties, but it was more of me just talking about all of the things that I struggle with and there was very little back and forth to the conversation. This was what I wanted for an initial conversation, but it is time to move beyond that. I need to do some education on OCD in general. I am planning at looking at some of the materials that the IOCDF has, but I know that I need to customize this for my specific problems.
As of yet I have not asked for any specific help from my wife or son. I'm not really sure how they can help yet. I suppose that this isn't completely true. I have been doing imaginal exposures where I talked about killing my son before killing myself. At first I could only listen to this when my wife and son were asleep. I can now listen to this on headphones while they are in the same room. Being able to listen to this recording out loud where they could hear it as well would ramp up my anxiety even more. This is one way that they could help, by being present for my exposures.
I dont know if this will be of much help to you, but the way I educated my parents was through YouTube videos. I found a few that talked about fear of suicide and existential OCD, and explained to them as it went on how I could relate to it, and how my intentions are not to do said things, but rather a fear of them. I also emphasized that OCD doesn't at all make me any more likely to commit these acts than it does for anyone else. My parents are both a bit OCD themselves (in a check the stove a bunch of times kind of way) so I found an analogy online about how this situation is a similar obsession/compulsion pattern but just different context. It's still a learning process, and some people will have different reactions, but my parents have been very supportive whether or not they fully understand.
Depending on how old your son is, I don't know if I'd share the exact content of the thoughts (not that it's to be ashamed of at all because it's not real, but just because if he's young he may not fully understand and be afraid). This obviously isn't something for me to have an opinion of as I don't know you or your son, just something to be aware of. Just do your best to evaluate the situation and potential outcome first. 
My son is 18, soon to be 19, and headed off to college in the fall. I've been thinking of trying to talk to my wife and son together. I'm not sure if that will work or not.
Oh, scratch that then -- I just turned 20 so I'm sure he'll understand. Maybe try talking to your wife first? It might be overwhelming for you to talk to both of them at once. And if you get your wife to better understand, she'll be able to help you explain it all to your son.
My family and friends know I have OCD, I have one friend I tell everything to and my partner, and that's only been recently I've opened up about the intrusive thoughts!!
My partner gives me a different way of looking at my thoughts, and doesn't tell me not to think about it anymore, I think what non sufferers don't realise is the repetitive of it all.
I don't know if this helps, but that's what it's like for me.
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