<human>: Could you distill the essence of the text into 1-3 sentences?

I'm a girl who loves kissing. I can honestly kiss someone until my lips start to hurt. It doesn't have to lead to sex, I just love making out. It's one of my favourite things in the world and always have been, especially with someone I have feelings for. My boyfriend was not a exeption, when we first started dating we made out for hours, and even a long time into our relationship we never stopped our passionate make out-sessions. So this is why I'm confused to why this has happened, it's totally not like me.  
  
  
I've been with my boyfriend for 1 and a half year. Great boyfriend, great relationship. But I can't remember the last time I wanted to make out with him. I do want sex though, and I still find him attractive. We have sex just as often as before. We would make out for a while before doing it, but now it just feels like a obligation and I feel like I just want to get it over with so we can have sex.
When we have sex he wants to kiss me before or during and I just turn my head away as fast as I dare. 

I do enjoy everything else about being in a relationship, like holding hands, sex, cuddling. I love sleeping next to him, spooning or just hugging.  
  

When I see someone else i'm attracted or when I fantasize I think about making out, so it's not kissing on general I don't like anymore, just not with my boyfriend.

I've been having some issues with him for some time which might be a factor in this. I have been tired of him being lazy and unmotivated and even though we have talked about it and him getting better, it's still somewhat of a problem. That's the only explanation I can think of, but I don't think it's a legit one since I still find him attractive, likes spending time with him, want's sex etc. And I'm pretty sure this kissing-thing started before that started affecting our relationship. I'm hoping it's just a phase, but it's been a long time now so i'm starting to get more and more worried. Am I falling out of love?
<bot>: I don't like kissing/making out with my boyfriend anymore. I have always loved it until some time ago, what is causing this?