<human>: Could you distill the essence of the text into 1-3 sentences?

My best friend and I have been through a lot in the last 4 years, and recently we have talked about being romantically interested in each other. I already love him as a best friend, and am starting to love him romantically.

I was in an on and off relationship with someone [25 M] for the last 6 years. We started dating in September 2009, and broke up after two years, dated again for a short while, broke up, and then at the beginning of this month, we broke up for good, a couple months before our 2 year anniversary. 

We were very serious, I lived with him last summer. Found out he was lying about a lot of stuff and once talking to him about breaking up he said he wouldn't talk to me ever again and blocked me on all social media. I had come to resent him near the end of our relationship, and think I may have emotionally been detached for a couple months.

My problem is I feel like this relationship with my best friend may be moving too fast. We already know each other very well, and trust each other. We have a lot in common and I can see myself being happy with him. We both want to make it official, and start dating, but I keep telling him it's too soon. He is really understanding about this, and had been there for me throughout my previous relationship. He never took advantage of me, and isn't doing so now. 

How long should I wait until I dive into this relationship?
<bot>: 6 year relationship ended early this month, best friend of 4 years and I are interested in each other, don't know how long to wait until we can date.