<human>: First time poster here; looking for any advice on this emotionally confusing situation..

We first got together when we were 16 (we met in college) and were almost instantly head over heels in love. Staying up late messaging each other was how it began and I soon found myself completely infatuated with this girl. 

As I started seeing her more and more (going over to her house, going out etc..) these feelings got stronger and what started as what felt like my first love turned into a four year relationship.

Like all relationships we had our ups and downs, we had our fair share of arguments and fallings out but they were always temporary and we always ended up into each other's arms again. This all changed however when we decided to go to university.

Without getting into too much detail I became somebody I wasn't and I thought at the time I'd be better off without her, despite this she tried her best to put up with me but after some time I guess enough was enough for her and we decided to split. I was devastated. I lost her. I snapped out of my immature haze and I realised what I wanted. But it was too late.

Now we're both seeing other people, but we still talk often. Just recently we had a massive talk about how we still love each other and that no matter how lovely the people we're seeing are they simply don't compare. This feeling is completely mutual to both parties; we both also feel equally guilty towards our partners for thinking these things let alone discussing them openly to one another. We've already said that there's no way we can get back together while we still have all of this negativity left over from our rough break up but my question is how do I proceed? Should I stay with the girl I'm with now or shall I start working towards trying to rebuild? I've always loved my ex and I know she feels the same, it's a very deep rooted love that we've tried to get past but it doesn't seem to be happening.

Can you give me the gist of the text in a nutshell?
<bot>: Broke up with first love of four years but we still talk. We're now seeing other people but we both agree it's not the same yet we still have reservations and guilty feelings about trying to make it work.