@trisha30
I don't think he wants her back.. He was the one who finished things and came back to me. She found out we were together again and initiated the total blocking but it was him who left her for me first.
Everything you know about his ex and their relationship has come from his mouth. Do you really think he wouldn't be filtering what he told you? Putting a spin on it to show him in a good light and cast her as being in the wrong / needy / an evil witch / not who he wants any more?
They were together for five years - from ages 18 to 23. A messy UNRESOLVED ending which maybe shouldn't have been an ending at all.
I'm going to rewrite the narrative given, because after all, you'll have put it through your filter.
Couple together for five years. Other woman decides she want this bloke, engineers it to make the woman think her DP has been cheating, she unsurprisingly ends it, devastated. Other woman moves in for the kill, man is flattered and does a 'Ross from Friends' (we were on a break!) but even so at first chance to rekindle his relationship he jumps at it. Woman still devastated and wary so the rekindling doesn't hold. Man returns to other woman with tail between legs but, bereft, digitally stalks his now-ex.
Now, obviously I don't know how close/far my fictional rewriting is to the truth, same as I don't know how truthful he is to you or how objective you are being in what you write here. All I can say with any certainty is that this is one big huge MESS, and if you had any sense of self-preservation you'd step back from it. Tell him to go and sort it out with his ex, because right now he is emotionally unavailable to you, unready for another relationship. Maybe they'll get back together, maybe they won't. But as it is, you'll never feel sure of him or his feelings for you. That's a really good way to kill your self-esteem dead, and set yourself up for a miserable life.
So yes, "confront him" - but not confrontationally! Tell him you know about the instagram account he uses to follow her online, tell him you don't think he's over her, and tell him to go and sort it out and only come back to you if and when it's sorted. You do not need or want a relationship based on such poor foundations.