I (35F) broke up with my partner, (35M) after finding out that he lied to me for being separated with his wife (34F). We have been together for almost 6 years with a 1 year old baby. I never met his wife. From what he said when we met 6 years ago, he was separated and is co-parenting their now teenager kid. He would tell me that he would be going on a trip with his kid, and his ex-wife will be there. He usually assures me that they are only in talking terms when they need to discuss about their kid. I didn't think so much about this then. I've also been very busy due to work and eventually, care for our baby.

However, I noticed an increase in the frequency of him meeting his ex-wife and kid. His usual alibi is that his child is asking for him to accompany him in certain activities. It was a bit bothering me, but again, for my peace of mind, I shrugged it off.

He then moved to a new company, causing him to spend overtime in some days. I won't tell what exactly is his job, but it has to do with dealing with a lot of customers on a daily basis. This is when he asked if he can sleepover his brother's home when he is at closing shift, so he can save time and rest longer, instead of traveling for 1.5 to 2 hours. Since I wanted to prioritize his well being, I allowed him. He then usually goes home like half of the week, including his rest days. The for the rest, he stays at his brother's. (OR SO HE SAID)

Fast-forward to a few of days ago, John and I had an argument. Since we're not meeting halfway, he decided he wanted to spend the night at his brother's to cool off. I was asking him not to go, but he was adamant. He left and didn't say anything to me. I didn't contact him as well as I know he'll just be ignoring me for God knows how long. Usually, he'll be out for just a day, but this time, he didn't come home, nor contact me for days straight. This is unusual for him since he would still ask about our baby even though there is tension between is. He'll just ask how's our baby, and I'll be sending photos or a video, and he'll be ignoring me again.

On the 3rd day, as he was still no contact, I was already worried that something bad might have happened. Even though my messages would be delivered, he hasn't seen any of the photos I sent of our child (just to check if he'll be looking through our chat). I don't usually invade his privacy, but I felt at that time it was necessary for me to check how's it going. First I tried checking with his brother. I know this is a red flag, but for him, contacting his relatives without his knowledge is invading privacy. I sent a chat to his brother to ask if John was okay, and if he was with him, but to my surprise, John hasn't been to his brother's home for quite sometime now. He said he didn't know where he is, so I was kinda hitting a dead end. I don't know who else to contact. As I don't know where else he'll be staying. The next thing I thought of is to access his social media account to see who he's been in contact with. But this is when the shit hit the fan.

I thought first of his ex-wife. Again, we aren't friends or anything. I haven't met her even though our kids are half-siblings. They also live kinda far from our home. I didn't actually know how to approach her so I stalked for a bit. To my surprise, there were a lot of posts of them, as a family, and as husband and wife. All sorts of gatherings, from birthday celebrations, holidays, and even their anniversaries. I was so dumbfounded. In some pictures, he had his arm around her waist and he was kissing her forehead like they've been in love this whole time. This broke my heart, but then I realized, everything made sense. He was living a double life under my nose, and kept me from finding out by gaslighting me everytime I felt something was off. "Just trust me" he says. "There's nothing" he says. "It's you I love and ever dreamed off" he says. F*ck off.

And John was there alright. They were in a short vacation these past few days. Why he haven't contacted me at all. With a heavy heart, I saved those photos and screencapped some of the posts showing the dates. I felt cheated on, and much worst he made me the other woman in this scenario. I didn't want any part of this. So I used these later to break up with him.

While I was snooping around some more, I found something that felt like a punch in the gut. I saw his conversation thread with their previous helper (28F), which was the cousin of his wife, and found obscene chats from the girl to John. It looks like it has been going on for quite a while, and this made me feel like vomiting. I saved copies of that conversation too, though I'm not sure when I'll use it.

After a couple of days, I broke up with him. I showed him my evidence (with his wife only). I was expecting him to be mad since I invaded his privacy, but good thing he didn't. We broke up peacefully. I already felt that a heavy weight has been lifted from my shoulder, when I was about to close log out his account, I saw a chat he sent to the cousin asking her to meet him that night. I felt another punch in the gut. I didn't know what to feel. I lost respect to him as the father of my child. I didn't know what to do. One thing I thought of is to tell this to his wife, but I don't know if it's the right thing to do.

I'm also planning to go to the doctor to get checked. I think the only window I have to tell the wife is if I've contracted any STD. But if not, should I still tell his wife? Or should I leave it to karma to come his way once his wife finds out he's messing around with his cousin?

PS: He asked the girl to come to their house (while his wife is sleeping) in the wee hours.