I am a lost

I feel like I am completely useless. I have attempted 2 times before and was unsuccessful. I am 29 years old. I was married for 7 years as of the 1st of this month. I took a shot gun to my marriage. I think I am bipolar but I have never been seen for it, mainly cause I was am to afraid to actually be diagnosed with it. My marriage has turned to hell. I have been in many relationships and only ever loved one woman and I know Ill never love another woman like I loved my wife. I was never a good husband though. I would say stuff like Yea I totally like this or that and go back on my word. I had it really one sided if you can get what I am trying to say. I have been thinking of killing myself as of lately. I even bought some lime sulfur and a bucket cause I already have toilet bowl cleaner. I got everything I need to do to go peacefully and yet no one could care less. My soon to be ex wife is asleep on the couch sleeping and I might as well be a million miles away. This has been weighing me down for the longest now and I just felt the need to do this somewhere. I feel like I am just a burden on everything. I hurt so much and really no one could care the only one I love wants nothing to do with me I just wanna scream at her, tell her how much I am hurting but I know deep down it will fall on deaf ears.