Anyone traveled as a couple before ?? What's your experience/advice ?

I'm going to Thailand, Laos and Cambodia in October for 3 weeks. Originally, I decided to put together 3 weeks of my annual leave for some personal time to reflect on career, life plans, personal development etc. I'm in two minds about taking my girlfriend along because for starters I've never been on holiday as a couple before let alone backpacking and I have no idea what to expect despite trying to visualise it over in my head. I don't want to regret taking her, but on the flipside, it could turn out to be an amazing experience for the both of us.

Cheers !