Heart vs. Head which should win? Girl adivice Please

Please at least skim read this, I really need advice because I don't know what to do. Answer this before you just click away: which is stronger logic or heart?

I'm torn in the middle about my decision between two boys. My on break guy Tomi and my ex Dimitri. I need some advice on what I should do.

Tomi Con's

He's overwhelming. Complains a lot. Is 18 and not in college yet. His father runs his life for him. He always wants to see me and whines when he can't. He sucks up all my time away from my friends. He's annoying; he answer questions without knowing the answer or the topic!

Tomi Pro's

He's sweet, caring, and adorable. We talk for hours everyday. Very open. He's romantic and considerate of others. He's always helping people. He works. He absolutely loves me.

Tomi and I have dated for almost a year and it wasn't till he tried to break up with me via text over a month ago (we're past that now), did i start to lose interest in the relationship. He wants to fix our problems but I don't know if there worth fixing.

Dimitri Con's

Has hurt me in the past. Doesn't open up to much. I only could see him only ever so often. The biggest issue: He has a pretty, nice, and sweet girlfriend.

Dimitri Pro's

We just click; we can't NOT think about the other no matter how long it's been. He's smart, artistic, is into music more than I am (!).

The problem with Dimitri:

He want's to see me this Saturday and hang out. He says his girlfriend knows and is okay with him seeing his ex. What girl is okay with THIER boyfriend going to another town to see and spend time with his EX? I don't understand why he's willing to risk putting "what if" and doubts in his girlfriend's mind, and possibly put his relationship on rocky ground: just to see an ex.

The text he sent me when i asked him this:
One thing I've always had feelings for you and always will. Second, I the one who f***ed up our relationship time and time again and I remember wanting to call you so bad to say I'm sorry and I regret what I did and you not wanting to talk and hating me and having a s***load of tension. That is what I'm nervous about (for this Satuday).

The text after that:
Hey hey hey, never said i found my soul mate and I care for you. I don't know. It's complicated to explain.

This Saturday, I want to ask him so much. Does he still regret ending things? Would he try to get back with me if he had the chance?