Scared to tell my husband 😭please help

S • ‘16 MC, ‘17 boy, ‘20 boy

I might be pregnant again.

We only had sex once this cycle and he pulled out perfectly so as to not get me pregnant, he doesn't want another child (at least not right now).

If I am pregnant and I tell him, he's going to think I must have slept with someone else. Hell I won't blame him, I'm in utter disbelief as well. It like, couldn't happen.

I know there was a tiny chance of me conceiving especially since it was my first cycle after my pp return of AF from breastfeeding. I'm told you're extra fertile??

Is there anything I can tell him to help him believe that it was him that knocked me up in that slim chance, that I wasn't cheating?