Been married 6 years- SOOO unhappy and confused? I feel like I'm losing my mind.?

Been married for 6 years now, have a beautiful daughter who is 4. My husband at first was very loving and friendly, and didn't smoke weed, like he did when he was in highschool. He is back to smoking weed, watching tv, not paying attention to me, not touching me, and has a bad temper or he'll say hurtful little things. I don't know who he is anymore- I can honestly say- that I don't love him anymore and it makes it hard because every day of my life I have to fake it...because we have a daughter. So, I haven't felt wanted in a very long time- but- the plot thickens- He seriously hasn't touched me in months- He even get stoned the day before Thanksgiving and it was everything I could do not to yell at him and tell him what a moron he's become. The plot thickens though- so, he hasn't found me interesting at all, and doesn't pay attention to me, and I've actually lost weight from stress through the months and am 130 lbs, now, and guys are hitting on me all the time. Well.....I've started talking to an ex-flame and I do say flame because things were hot between us- and I know that's not the thing to do either- but geez- I so don't know what to do. I want to feel wanted again....Can anyone relate? I think my husband and I have ventured off course to far- He was into the pot smoking, video game playing crap in school....and I was never into that. It's sad to say, he just doesn't find me interesting anymore- and I don't find him interesting either.... BUT- we love our daughter, and I don't know if this means I have to go through the rest of my days with a husband who doesn't know I exist as my stress level from all of it makes me keep dropping weight to where I can't eat for days.... It's so depressing- to know that when you marry someone and they put up a front to begin with and then this whole other person you didn't know about comes out- It's like WTF? He hasn't said I love you, or touched me in months- MONTHS- I just feel so undesirable- but obviously I'm not if guys are hitting on me right??? God, I'm so confused..... So confused.....