Should I still want to be with him?

I broke up with my partner about 8 months ago,.... we have not stop[ed being in contact since. and talk daily. i found out he had been seeing a girl on a dating site and they planned a trip away together. we then became really good again and were almost back together when this trip came up. they hadn't seen each other for a while before and are going as 'friends' but im just worried things may change again with us. i wanted him to not go on the trip but he didnt want to be the guy that cancels. its so hard to this they are away on a holiday together (there are other people there too not just them but they are sharing a hotel room- separate beds) while im here waiting for him to get back. hes talking to me heaps while hes away but i cant help but be uncomfortable with the whole thing and am wondering how it will affect us. he assures me he only sees her as a friend.

It's called, hedging his bets. If you and he don't work out a second time, she's there waiting in the wings. And vice versa. Because once it'd become clear you were hoping for full-on reconciliation, that was the point where he should have thrown any other fishies back into the water. And yet he didn't, he hung onto her. "Friends", my arse. He may not want to DO anything with her any more. But that wouldn't stop him from liking the fact that this "friend" makes you feel constantly threatened. Because if you already feel you could lose him at the drop of a hat then you're unlikely to want to rock the boat, even if/when HE'S the one who makes it necessary. So let's get this straight: he doesn't want to piss off a mere friend (by the nature of that title - short-term) but doesn't mind pissing off the with-a-view love of his life? Doesn't want to throw away a handy tool, more like. If she's only a friend then compared to you AND the quality of your relationship as is dictated by your being calm and happy (surely?!) and capable of investing your trust, then she is entirely dispensible. "Just a friend" is as "just a friend" *does*. Ultimatum him (and mean it). You might think that could sound the death knell to your relationship parte deux, but it's a win/win situation for you because if he IS just using her as his Sword of Damocles, in which case it would be a manipulative way of testing how serious about being in it to win it YOU are, then he's doing it for reasons of insecurity, meaning, your putting your foot down will reassure HIM. That may be what this nonsense is angled towards. It usually is. Especially when, there they are, supposedly with something between them, yet there he is constantly texting you. She must be well boring, eh. ;-) Your alternative to ultimatum-ing him is to just ignore-ignore-ignore, by which I mean, LIKE IT'S NOT EVEN HAPPENED. If a button fails to yield the desired response, despite they might try a second or third time (and harder), no human will continue beyond that point with what has categorically proven to be an exercise in futility. But he's not your 3-year-old son who requires emotional managing so... my vote is, put your foot down. If you prove YOU'RE in this to win it then the responsibility and culpability for whether or not this relationship continues and succeeds falls fairly and squarely at his feet, does it not. Which is where it SHOULD be, considering he's the one acting up.