0 friends and I need to vent.

How do you just end a relationship with someone after 4 years? You love their family and you love that person but you’re not feeling the love back. I feel like we’re just in such a routine where we love each other but we’re not IN LOVE anymore. I feel like I’m just THERE, I’ve caught him texting other girls, going on hangouts to send dirty pictures and dirty talking but I’m right here and he doesn’t even want to touch me? He denies it, even though I pretended to be someone else just to catch him and he still Denies it. What’s wrong with me? Why don’t I look good enough? Like I don’t understand why someone would stay in a relationship with someone they clearly aren’t attracted to anymore. I’ve tried to end it with him but I’m SO scared of being alone. Like how do I live without someone whose been apart of my life for almost 4 years? I know it’s not healthy for him to tell me to shut the fuck up and get the fuck out of his house every time we fight. I know it’s not healthy that I just discovered he was doing a line of speed every day before work, but if I bring any of this up I’m the crazy one. I’m stupid and I’m ridiculous. I ask questions about his friends or how is day is, he sighs and just gets an attitude. I’m so tired of not feeling worthy enough for anyone