He does have some traumatic events by now in relationships with Mars on the DC and Venus in Scorpio.He doesn't lie about that.
You should be able to express feelings. Your Moon is in his 7th whole sign house and his Sun in your 7th house in Sag.
Maybe he's still going through it. He's a Pisces ASC, he is normally going to be impacted emotionally by this. It's not going to be as expressive or moving forward so easily.
Normally, without astrology, this is a red flag that you dated him before and he went back to his girlfriend and now he's back in ur life. A past behaviour will repeat itself. That's for sure.
I wouldn't do it again, but do as you think it's best for you.