I started dating this guy, we'll call him "Joe" about two years ago. For the first few months of dating, everything was great as it usually is in the beginning. I did notice that he had a lot of female friends on Facebook. I don't have a Facebook account, but he used to scroll through it on his phone with me next to him.
One day, about a month or two into our relationship, he was at my house and received a call and spoke with a female friend of his who was in a female prison or halfway house. I tried not to listen in, but at the end of the call he said (right in front of me, not hiding anything) "I love you! Bye!" He then told me a sad story about this woman who had been his friend for decades, who had been incarcerated for holding drugs. He said that she didn't do anything wrong, and he "had no reason not to believe her." I think that is naive of him, but whatever. He told me they had never been romantically involved. He told me he was sending her some money, and that she was looking for an iPod or something for music. I had an old iPod, but it wasn't new enough for her, in his opinion.
Over the next few months, he kept talking about her, explaining how they met, how his friend had dated her. He told me about her ex-husband and children. He told me how she'd looked the last time her saw her (how she looked like she was on drugs, etc.). When we were together for about five months, she was released. She messaged him through Facebook while we were at my house, and they had a little back and forth, exchanging numbers. He did say that he was "at his girlfriends house," and showed me her picture, saying she used to be prettier. Since then, he's completely stopped talking about her. I started noticing when we were scrolling through his Facebook that her name kept popping up in posts and messages, and he would quickly swipe them away.
Fast forward to now - I bought a house, and he's moved in. He stopped looking at Facebook in front of me completely, and I asked a few times, but he always changed the subject. To note, he is chipping in 1/2 of everything financially, but not chore-wise. A few months ago, we were looking at YouTube videos on his phone, and an alert popped up about a Facebook message from her. He made an offhand comment to the affect that "she sends me crude photos and videos."
Now here is where I did the wrong thing. I checked his Facebook from his computer, where he was always logged in. I saw such disgusting videos of naked women, references to dildos, oral sex, etc. coming in direct messages from her. I confronted Joe, under the guise of him telling me that she was sending him crude photos and videos, and asked him to tell her to stop since I didn't like it. He flipped out, changed the subject, and then said he'd delete his Facebook account. I told him I didn't want him to delete his account, just tell her to stop the filthy messages. He said he wouldn't do that, he'd just delete his account.
He's since re-activated his account. BUT he hides it 100% from me, doesn't get any alerts at all on his phone anymore. I horribly looked at his computer, and he's not logged in anymore, but when he looks at his email in bed I see his notifications from Facebook, which he quickly swipes away. I've asked him several times about her, why I haven't met her if she's such a good friend, and he says that its because she lives 2 hours away. We've visited people 3 hours away, 17 hours away, etc. I'm ready to end this over someone I've never even met. Not because I think he's cheating physically, but because he won't be honest with me. Am I being unreasonable?