<human>: Can you summarize the given text in a few sentences?

My boyfriend (28)  and I split in december last year, we were together 8 months. The relationship was pretty good, but in the last month or so we argued alot and he seemed a bit distant. We ended up having an argument and breaking up. I thought we would make up but we didnt. I was and still am madly in love with him.

I found out he was dating someone quite soon after me, he met her whilst we were together. He said he didnt cheat and she isnt the reason we split. I do believe him about not cheating but not so sure that she wasnt a factor in our break up.

Fast forward 3 months and they are no longer dating. I had started dating someone casually for a couple of weeks but i was going to end it anyway as it wasn't going anywhere when i recieved a letter from my ex through a mutual friend.

He explained how much he loved me, us breaking up was the hardest thing ever and he has thought about me each day since etc.

We got in touch and he asked for me back. I didnt realise how strong my feelings for him were until i received that letter, they all came flooding back.

We have been back together for nearly 3 months now. Everything has been amazing, he has been so romantic and loving, its been hard getting over what happend in the months apart with the other girl but we both seem to be working hard to make it work. We did have one argument over something unrelated but made up very quickly.

However im so scared he will be distant again, or leave me for another girl. Ive done my best not to let my trust issues effect the relationship. He has been very understanding.

Has anyone else taken back an ex after they left you for someone else? I still dont know if she was the reason we broke up but it felt like it. 

I love him so much, in his defense since we have been back together he has been amazing. But im just scared we will break up again if another girl comes into the picture.

Im looking for advice and experiances from people that have been through similar.
<bot>: took back boyfriend after he got with another girl straight after we broke up. Everything is great but i worry it will happen again?