SO lying

so my SO and I are in a poly relationship. we're also long distance for now. today he said he was going to have sex with someone and I was ok with that. I asked when he said a few hours. etc. he eventually told me it was a friend of his she wanted a kid but didn't want him in the picture and I was chill with it. eventually told me he came in her, that it was good, etc. eventually said he came in her a second time and was laying down naked I asked him if I could see a picture of him and he said no cus he was all sweaty from sex.

I was a bit annoyed today because he keeps saying he will come see me but never does and so we talked/argued about that then all of a sudden says"I didn't even have sex today, I haven't had sex in over a year"

I was taken aback cus he made a fairly detailed story about having sex, who the person was, etc just to tell me he didn't have sex. and honestly idkw he would feel a need to lie and make up a story about whether he had sex or not. it's making me question his integrity. if he can't tell me the truth about something so small what else is he lying/making up? when I asked why he lied he said "I don't know"