Have I been cheated on?

[LivelyTurtle]

I've been with DP for 6 years.

Recently was diagnosed with trichomoniasis after pap/colpo (incidental finding, they werent looking for it), never showed any symptoms but have suffered yeast infections over the years.

He's probably had random itching over the years but no proper symptoms.

I never even heard of this std until the doctor mentioned it.

I've read its possible to have it for years but really it's hard to not think he cheated.

Can someone talk me off the ledge I'm devastated.

Trich can be transmitted through non sexual ways, though less frequently than sexual, but it's possible and not rare.

I don't know what trichomoniasis after pap/colpo is?

I had abnormal cells on a pap smear so was sent for a colposcopy. I had an inflamed cervix so they tested for stds.

Have you asked him?

Yes he said he's never cheated and I believed him, we've been together a long time and he's never given any reason for me to believe he's been unfaithful

Has DP been tested for trich?

Yes he tested positive also, took the antibiotics before his results came.

Either one of you could have originally caught it before you'd got together?

Or DP could have contracted it in a non-sexual way and then transmitted it to you, OP. You've told us that he's never given you reason to believe that he has been unfaithful.
Have you communicated your concern to the GP?