Would you believe him?

[Gaelicburger]

Hi. My partner of 20 years admitted a few weeks ago to cheating on his previous girlfriend when they were about 22. I can't remember how it even came up in conversation. He said he met up with a friend of theirs one weekend, went for a drive, did lots of 'other stuff ' but didn't sleep with her.
Bear in mind I caught him sexting an ex 5 years after we met. So now he's done it twice to two different people.
Lately, I'm assuming due to perimenopause,i am joining the dots and am beginning to ask questions about everything in my life.
So would you believe him or not?

Well, he cheated on you so he may have cheated on her too.

I'm a bit confused as to the question you are asking. If he was doing sexual stuff with another woman , even if he didn't " sleep with her" - I'm assuming that's a euphemism for full penetrative sex?- then yes that was cheating on his gf at the time. Similarly sexting another woman when he was your partner is cheating.
So what is it you don't know what to believe?