Hi all, I am new to this forum and I just signed up to start this thread. I am in real need of advice.
6 months ago I was dumped out of the blue by my then-boyfriend after 18 months together. We met very shortly after he ended a 16 years marriage with 3 kids. His life was understandably a mess. He is 14 years older than me, and a good, honest person I think. I am 32, no kids, never been married, a good stable job, financially independent, and reasonably good looking.
The relationship was a whirlwind experience, we fell madly in love quickly and were crazy about each other. Sex was amazing, big love declarations after a few months, blissful happiness. With the benefit of hindsight, I know, it was probably a rebound for him, although at the time the feelings felt very real. The relationship had a lot of logistic limitations as he had his DC 50% of the time, so we could only see each other a couple of times a week, but we managed. I never met his DC as we both felt the time wasn't right yet.
6 months before he broke up with me, his life took a turn for the worse, he quit his job and couldn't find another one, his ex-wife started talking about moving to a foreign country with the children, his financial circumstances got difficult and he started struggling with depression and anxiety. He started displaying worrying behaviors like not getting out of bed and not leaving his place for days, OCD tendencies, inability to sleep at night. With the benefit of hindsight, I also realise that the relationship was entirely on his terms, since I was so conscious of the fact that he was going through a difficult time, so everything revolved around him, his schedule with the DC, his mental struggles, his moods. I felt the responsibility to cheer him up and help him get his life back on track
Eventually he ended it in a very dramatic way, saying that he loved me to death but he couldn't handle the pressure of a relationship on top of all the other pressures he had in his life, and that he couldn't offer me what I deserved, and that he couldn't stand the idea that he kept failing to make me happy. He said perhaps he wasn't ready for a relationship and he needed time to sort his life out. All very dramatic and martyr-like.
This came out of the blue and it really knocked me for six. I had a horrendous couple of months, I just couldn't believe he could give up on "us" so easily. After a while, I pulled myself together, felt better, got out there again, and started dating. 2 months ago I met a lovely guy who I have been going out with. I really like him, we have a great time together and I think things look promising. He is also around my age, no kids, no previous marriage, good job, financially stable.
However, a few days ago I got an email from ex-boyfriend, who essentially said that he has spent the last 6 months working on himself and doing therapy, he feels much better, he is actively looking for a job and feels like he's got his shit together. He has never stopped loving me and hopes I would consider giving him another chance, even though he understands if I never want to speak to him ever again.
I am so lost now. I haven't replied yet, as I don't know what to say. On one hand, my feelings for him are still there, and my heart aches at the idea of saying no. I so wanted our relationship to work out. On the other hand, my head tells me that that relationship was never going to work out anyway, as there were so many challenges: different life stages, different lifestyles, his parental responsibilities, his emotional baggage.
New guy is so nice, it is still early days but I think the relationship has a much better chance of long term happiness. I feel so torn.
What do I do? 
Thanks!