How to deal with long periods without sex?

Hello fellow redditors. I apologize in advance if I'm not where I'm supposed to be with this, but lately I'm having a hard time with my girlfriend gone. She works in another country, and for one month (or more, sometimes) she is gone, followed by one month home. Now she's gone for almost 3 weeks, and it's been harder than normal without sex. A new colleague at work started showing interest in me, and even if I told her that I'm not single she doesn't seem to mind. I haven't made any advances or anything, and nothing happened, but I'm really struggling with intrusive thoughts while I wait for my girl to come back home. I'm not even sure what I want from you guys, maybe just to vent. In the beginning of the relationship, we used to have lots of online fooling around, and we're both on the kinky side which made it quite fun, even if we weren't close we could still find sexual release there. But lately that died down, and it turned to the occasional dirty picture, mostly initiated by me. Thanks for reading and ...give an opinion if you got one.