There are two separate questions here and they get tangled. Should your partner know you’ve OCD? Almost always yes — it shapes your life and theirs, and they’re probably already accommodating it without a name for what they’re doing.
Should your partner know the exact content of your intrusive thoughts? Often no, or not in detail, and for reasons that are clinical rather than about shame.
Why detailed disclosure often backfires
Because it’s frequently a compulsion. You say the terrible thing hoping to be told it isn’t terrible — which is reassurance seeking with a moral frame, and it produces the familiar four minutes of relief followed by a need to say it again, more completely, because the first telling now feels incomplete.
And it lands hard. A partner given graphic content about harm or taboo themes can’t unhear it, has no framework for it, and is left managing a fear they can’t resolve. Partners in this position are sometimes genuinely traumatised, and they rarely say so, because the person they would say it to is already suffering.
What to say instead
Give the shape rather than the script. Something like: I have OCD. It attaches to whatever I care about most, which means I get intrusive thoughts about things that horrify me — including about you and the children. Having them is a symptom, not a wish. What I need from you isn’t reassurance, because reassurance makes it worse.
Then explain the loop briefly, and — the important half — say what you actually want them to do. Most partners are enormously relieved to be given a job that isn’t endless reassurance.
Doing it in a session
The best version of this conversation usually happens with the clinician present, once, early in treatment. It takes an hour and it does several things at once: your partner hears the explanation from someone with authority, they can ask the questions they wouldn’t ask you, and you can agree together on the accommodation plan and the exact words they will use when you ask for reassurance.
Clinicians will often suggest this. Ask for it if they don’t.
If you’ve already disclosed heavily
Common, and repairable. The move is to name it: I have been telling you these thoughts to get relief, and I have learned that it feeds the OCD and that it has been hard on you. I am going to stop, and here is what I would like us to do instead.
That conversation is worth more to most partners than any amount of further explanation, because it names the thing they had noticed and couldn’t say.
New relationships
There’s no rule about timing. A reasonable approach is to mention the diagnosis when the relationship is getting serious, in the shape-not-script form, and to leave detailed content out entirely — including later, since the argument for full disclosure is usually the compulsion talking.