Problem with ex

Hi all. Well this is my first post and I'm really confused right now.

I was dating this girl for 2 years + and had to be in a LDR due to studies.
During the time while I was away, we broke up and I got to know that not long after that, someone was after her. They became closer and closer and been going out a bit.
During the mid year break, I came back and we started going out again. We didn't officially get back together but we started holding hands and did those stuff couples would do.
Then I had to go and then she started ignoring me.
And now, I'm back for good and initially started off by texting a lot.

She did happen to give me some signals like I really thought we still had a chance.
However, I realised that sometimes when I would like to ask her out, she would give some excuses.
There was one occasion when I was going to pick her up from somewhere, I happen to see the other guy around there.

What should I do?
To go or just stop it there?

Trust your instincts. You might not be able to prove it yet, but you have good reason to believe that she is still seeing this other guy. And due to the LDR situation, he got to spend a lot more time with her than you ever did. You should probably stop seeing her and move on, because they probably share a closer relationship than you ever had with her.

I've tried asking her that whether she has been seeing him. She denied it and said that I like assuming things.
Fact is that I'm really confused. Because I still have a lot of feelings for her and just not prepared to move on yet.

Stop looking at her as a girlfriend. Look at her as a **** buddy. Don't even think about exclusivity with her until she is sleeping with you and demanding exclusivity herself. Keep after other girls.

Or just tell her not to contact you unless she wants to get back together. You sound like a sap though, sorry to say. Probably time to just move on.