So I've been going out with this guy for a 13 months but I've known him for 6 years. I feel like over time the spark is going away. He's not like he used to be with me, all extra lovey and stuff. I know he checks out other girls, it makes me feel bad about myself. He says I'm the one and he loves me, but I just don't know. I want us to last but I can't stay with someone who I am not sure about. We argue more now and it sucks. I don't know if I am over thinking the relationship but I do know that you aren't supposed to feel bad in a relationship. What do I do? I'm confused and upset. But I think I'm losing my love for him. HELP!!

Only you can decide if this relationship is worth fixing, worth staying in. If you no longer love him, then you need to end it.

I do have to ask what checking out other girls has to do with anything. Everyone checks other people out, it's part of being human. If he's not cheating, than being jealous because he looks at another girl, is very silly. Is that what your fights are about?

If you are losing feelings for him and you are not happy, get out of the relationship.
I know boys will look at other girls but some can be disrespectful about it, however I get the feeling this is not the rel reason.
Perhaps the honeymoon stage is over and the thrill of the relationship is gone. Only you can decide if you want to stay in this relationship. That is what dating is about. You don't have to stay if you're not happy.