I need some opinions on some different things.

Okay so here it goes, my boyfriend and I, have known each other for just over a year, and we've been dating for 7 months and he tells me yesterday day well things don't seem the same, like the texted, and sex. 
We don't live together so have to resort to texting all the time, and as for the sex I'm knew to it and well i don't really know what to do or how to get him to make me orgasam. Like we don't just do missionary, I go on top of him( and it used to make me) and from behind. 
Now the thing is a don't want to lose this guy, he's picked me up when I truly didn't want to get back up my feet and he's made me so happy and does so much for me, he's honestly just made me a better person, and I'd keep going on with everything but that's not really the point of this post so yes..
I need some advice on how to spice up our realationships I guess. If you could please help I'd truly appreciate.