Hi, and welcome. If I could offer some contrary advice, it is that playing your characters in a relationship may not be the best idea. My wife and I almost never play an IC couple, for a host of reasons, but we have other workarounds for the situation you describe.
Firstly, literally no-one will question you sharing an IC tent with your OC partner. Like people wearing glasses or wearing modern boots, it is just something we automatically gloss over and don’t notice. If you do want to put a fig leaf over it, your characters can be friends, of family members.
As to reasons why not to play a couple with your OC partner, some people do it, and I guess if that makes them happy, fine - but I always think it is a route to unhappiness. Personally I’m quite expressive of emotion to my wife, and telling her how I feel is important to me. But when I do that, I want it to be very clear that it is a sincere statement. When you are in the field it can end up feeling a bit weird, like you are confusing your character and yourself. After all, you want your characters to be distinct people, not just you in a silly hat. That is really important to preserving your mental health in a long term game. If the character makes a terrible mistake and gets shouted at, it’s easy not to take it personally - that was them messing up, not you. And if your characters have a shouty argument, that is your characters. The bad feeling between them will stay in the game, not leave you having a very frosty drive home.
Plus if/when one of you messily dies, it is easy to then share your tent with another friend who just showed up.