Search Results: confused by an ex

My boyfriend and I have been together for over a year
A little background info:
Last year on end of July, when we first met, he told me that he is still friends with his ex girlfriend (they were together for 3 or 4 months)
He broke up with his ex around end of June
So they remained friends until August
He said they had a fight about something and he also mentioned she kept talking shit about me
When they were friends, he told her about me and how we are going on dates
And he said she probably got jealous because she kept saying that I was probably dating other guys and thats why he stopped talking to me for a while
But then they got into an argument so they cut off contact for good
And then we started talking again around September last year and then we started going out together more often and became official
Thing is, few nights ago, he mentioned that "girls and guys cannot be friends"
And then i said "but you and your ex were friends?"
And he said "yeah for a month. Look at how it end up? She was talking too much shit so I ended it"
What does this even mean?
doesn't this mean they both still had feelings for each other when they became friends after their break up?
Which means he still had feelings for her when we first met and going on dates?
Why would they argue if theyre just friends? Is that possible?
Im confused
I know its the past but I wanted to know what this means...