1. Remember you’re not single.
There’s a difference between how you travel when you’re single — “I think I’ll just buy this last-minute deal ticket to Hong Kong because why not!” — and how you travel when you have a partner. Before you go, discuss your plans and make sure you aren’t going to their dream destination without them, or scheduling your trip at the same time as an important event they hoped you’d go to together. A woman I know had a newborn and her wife had taken three random solo trips without consulting her since the baby was born; not cool. You’re an adult, you know how to be in an adult relationship — take your partner’s needs into account, treat them the way you’d like to be treated — so just take that relationship and do it when one of you is temporarily in a different place. If you’re away because you’re traveling a lot for work, that’s different; a job that keeps you away 5 days out of 7 per week with no foreseeable end date in sight might be cause for some renegotiation. But otherwise, just…don’t be a jerk.