Feeling confused and just guilty every day

I am struggling with my new girlfriend cause of my past relationship where I lost my partner in a sudden accident. My feelings are every where still after 2 years and I feel cant commit full emotionally to most things after I lost everything before with no warning!! I do really like this girl and she is trying her best to help me but I can see I’m really making her life hard at times and I don’t like it. I don’t no what I’m going to be like from day to day some weeks it’s just like were flat mates instead of lovers. I can’t help these feelings they take over me and it’s going to ruin us. We do talk about what im going through but i dont want my life sentence of grife to rouin hers she deserves better.