Ex went back to ex

[Kf3495n]

I am just looking for some opinions on a recent relationship I had as I am really confused and shocked at what I have found out. I was recently broken up with two months ago by my ex as we were arguing a lot - a lot of these arguments were due to the fact that I felt really uncomfortable that he still shared his dog with his ex however wasn’t keeping me in the loop about it. We got together about a month or two after they split (they were together 4 years) but he told me they were completely finished and there was nothing to worry about. He told me in the last year of the relationship he felt really unhappy and trapped and ultimately ended up on anti depressants because of it. They split for a month, moved out and back into each others family homes. They then got back together for around 4 months to try things again however he ended up splitting up with her because he was so unhappy. He told me when we got together he knows that if he is ever unhappy in a relationship again not to pursue it and leave which ultimately is what happened with us as we were arguing a lot. He was very cold with me and the break up was so abrupt. I had blocked him on everything but have recently found out that a couple of weeks later him and his ex have rekindled. 

I know I am now better off but I am just a bit confused after he was telling me how unhappy he was in their relationship to then get back together with her after he had said all this. Is this someone who can’t fathom being alone?
 

[basil67]

I'm sorry this happened.    He could have been saying that he was over her because he wanted it to be true.  Sometimes people can have a great deal of trouble leaving a bad relationship.  The fact that he stayed for as long as he did in the relationship with you and all the repeated arguments does suggest he has difficulty in walking away from toxic situations

In future, if you find the choices of someone in a relatively new relationship unacceptable, tell them you're not OK with it.  If it doesn't stop, enforce the boundaries and end the relationship.  But don't get into arguments because it achieves nothing and only makes the relationship toxic.  Always remember that it takes two to argue

[MsJayne]

No surprise that you feel confused and shocked. Maybe the reason you were arguing a lot is that your intuition was telling you to be wary of the connection he maintained through the dog. Turns out your intuition was spot on, so there's a reason to celebrate. Another reason to celebrate is that he wasn't much of a catch anyway, he can't even be honest with himself, let alone with someone else. He'll break up with his ex again, but hopefully you'll have long moved on if he has the nerve to contact you.