Can't stop obsessing about my ex

Block him on all forms of social media. Delete all his contact info.

You are only picking at the scab by continuing to check on what is going on with his life.

You want to know a secret?

He's not checking up on what you are doing with your life.

So go and do something. Take a class. Volunteer. Visit your folks. Go to MeetUp for something you enjoy.

That is, fill up your time with things that are not him. And you'll start to find you've spent an hour free of thinking of him. And then try for two hours, etc.

If this seems impossible, then seek out therapy.

Getting over someone takes time.

It does get better, but you really have to see the ridiculousness of obsessing with something from the past. You probably are not seeing this person for what he really is, after all, who would hurt you like that?

Don't give this a life of its own. Your life is passing by!!

Perhaps you didn't get "closure" or it didn't end the way you wanted.

I am in such a similar position to this, I have had a long-running break up, so that makes it harder to get over I guess. It is hard to explain everything without providing the background, so I will apologise in advance for the length of my post. Here goes.....

My ex (I HATE calling him that) and I were together for over 9.5 years. For the first 8+ years of our relationship, we worked together in the same office - not in the same team though. He moved in with me quite quickly (within less than a year) and so we spent 24/7 together almost. When we weren't together, we would talk a lot (for example if either of us was away for any reason).
He was getting tired of his job because there were few prospects and researched into what he could do to change things. This meant leaving home (due to where we live) to go into training, which I fully supported, as I was sure that if he stayed, he would only end up resenting me for not supporting his dreams. The training would last 2 years. But it was fine - it was all part of a plan for our future. I was really afraid it would cause issue in the relationship, but he assured me that he was doing it all for us, and a better future together. I couldn't move to the same location due to my job, but traveled a lot, and we managed to see each other far more than most in a long distance relationship. He constantly reassured me that everything was for us, especially when I was a little distant at one point - I guess I was feeling lonely.

In December, 2 weeks after seeing him, I saw him again and he said he wanted to break up - his feelings had changed. I felt like my life had ended. I struggled on through, but still spoke to him, which was probably a mistake. He did continue to tell me he loved me etc etc. Early in February I had noticed him interacting with the same person over social media. I asked him who she was and he confessed he had been dating her. Cue full on emotional anxiety. I felt like I had been stabbed. The physical pain of the heartbreak was shocking. I had to be signed off work as I couldn't concentrate on anything. I spoke to him and said that we needed no contact for at least 2 weeks (he was coming home 2 weeks later - to stay with family). He messaged me to confirm his plans and said he was struggling - we needed to see each other because he needed to know if there was a way back for us.

I agreed to meet him to talk, where he said all the same things. I was willing to give it another go, as I love him so so much, but I asked him could he be sure to remain faithful when he was away? He was fully positive about us being together again.
He also said he really liked the girl he had been seeing, so wanted to let her down gently - but he said he shouldnt have been with her, he used her as a distraction - every time he was with her he thought about me, and what I would do in certain situations.
2 days later he turns up and says he cant make that promise - he just doesn't trust himself. There shattered my heart for the 3rd time.

Since he left, he has messaged me a few times; he keeps saying that he loves me, but he needs to sort his head out, as he clearly has issues going on (he always seemed to present only one side of himself depending on the group of people he was with). I did engage in chat with him, but I have decided to now stop. He has continued to see the other girl - who I am beginning to feel sorry for, as it seems he is building a relationship with her, but he had told me that he was using her, essentially. I also KNOW that he was with another girl in the last 2 weeks, and that he is talking to another one via private messenger.

I know everything adds up to him being a bad person, I really do, but he wasn't that person when we were together. I really miss him every single day, and I am devastated that my future has been taken away from me. I thought we were working towards a mutual plan, and all of a sudden it's all gone. The main reason I was given was that 'he didn't feel butterflies the last 2 times he saw me'. Well, frankly, I was delighted that I had caused butterflies every time he saw me for over 9.5 years - surely butterflies aren't there all the time?!!

Anyway, now I do not know what to do...I feel in my heart that we should be together, I am really struggling at times. The thought of him with someone else makes me want to cry every time, its like a dagger to my heart.
I understand that there will be issues on my part, but I can honestly say that I did everything possible to support him, to see him as often as possible, to keep the relationship strong. One regret is not visiting him just before the breakup, as I think it would have made a difference because of the time of year that it was.
Another difficulty is that he is step father to my daughter - she loves him, and he has been the only real dad to her. If he walks away from her, she will be devastated, as her real father has already done that. This will be the point that i will get angry with him...I will really be upset if he breaks the promise to her that he will always be there, but I am worried he won't, as I am sure that he hasn't even told the girl he is dating about her.

It is all such a mess. What do I do?!! I am tired of it being constantly in my thoughts

I'm going to give you almost the same advice. And I'm sorry this is happening.

But you have got to make a much cleaner break. This means blocking him on all forms of social media and deleting his contact info. He didn't help things by stringing you along (yes, he did) and claiming he could end or at least cool it with his new girlfriend.

He won't. Why not? Because it is over with you and it is on with her.

I am sorry if that is harsh but if you have to tattoo that on your forehead backwards in order to be able to see it in the mirror every morning, then do so.

And in the meantime, I know it hurts and, again, I am sorry. I know this pain, too! But there is a certain point when it turns into an obsession. You need to find other outlets for your time and your feelings. This means occupying your time and it probably also means counseling.

You can live without him. I assure you that you can.

As for your daughter, she can have her own stepfather-daughter relationship with him if she so chooses. She is, I take it, at least ten years of age. So she can call him up by herself and text him and the like if she wants to. And if she wants to see him or he wants to take her to lunch or the like, then I hope you will let her go and do just that. Even if his new girlfriend will be there (I personally feel that would be in bad taste, but it might very well happen) or he will mention the new girlfriend. Consider it like a divorce. Your daughter can have a relationship with him even if you do not.