Husband suddenly lasting longer

Ok I want all of your thoughts on this.

I've looked into it and have read several different things. Especially about how he could be cheating or masterbating more.

Recently my husband has been lasting a lot longer in bed, which is strange. He hasn't lasted this long since we first got married 6 years ago lol. He said he has noticed too and that it's weird. He then tried saying maybe it's because we sometimes go a little bit without it then when we do he now lasts longer. Which maybe could be true. But we have gone longer without having sex and he finished like normal. And we honestly now only go without sex when I first start my period, so about the first 3 days. And then we might skip a day or 2 every now and then. So it's not like we go actual long periods without having intercourse and even then, when I was pregnant I absolutely didn't want to be touched and we would go damn near a month without it and when we would he would honestly finish faster or the normal rate.

But now thanks to Google, my heart is racing.

Last year I caught him talking to this girl who works at this mechanic shop his work uses so he's there nearly everyday. He said it was nothing, she's married and has been for 15 years. He said they mainly talked about me because during last year I was going through PPD and had really bad confidence in myself. So he was trying to get advice from her. However he had these like quotes saved in his phone about flirting and having feelings for someone. He said that he was saving them to send me. Which i still call BS on. He also saved pictures of her in his Google drive, one was of her in the bath and that was the only "risky" picture. He swears it was the end of that, that he told her she was crossing line. But like he saved it?!!! Lol. Anyways he said he doesn't even talk to her anymore, yet he still has her everyday for work, and he kinda can't quit because he has a really good job with a great company.

So anyways, I'm concerned now that maybe something is going on there still. Maybe he is cheating? Maybe he's masterbating to her or just in general more? Idk! Am I being crazy? Does this stuff just happen?