Heart or Mind?

Short explanation of my current situation in my crazy life.

So I have a problem here. By problem I mean HUGE decision to make. You see, I'm currently in a relationship with the father of my child. He also happens to be someone I dated in high school and reunited with since. We have been together for almost 2 years now and have a 7 month old daughter together. She's great. Our relationship WAS great. Well now not so much. What's going on? Literally nothing honestly. My point of view is as so. I feel like I'm doing everything on my own. I work full time and take care of our child. I pay all our bills except one. I feel overwhelmed. I am independent and all but I feel like I'm taking care of a grown man the same way I am taking care of my daughter. I love him to death though and I have no clue why! Well the biggest problem is.... I'm still not over my ex who I broke up with in 2011... We have talked on and off the last few years and apparently he still talks about me once in a while. STILL not the biggest problem. He has a girlfriend! They have been breaking up once in a while. Why do I want him so bad? I am not happy in my relationship and I am literally depressed all the time and have no clue what's the cause for it. I guess I am just not meant to be with him maybe? I want my ex. I know they say exes are no good, but I can swear to you that he was the one who got away. Recently I have gotten a lot more depressed because I want out of my relationship and just want my ex. My mind is so confused. Do I go with my heart or my mind?

Author's Note

What should I do in this situation?