Hi Peach!

Oh, a tough dilemma! I don't have any advice per se, just some questions to help you mull it over!

You said you would be devastated if the partner came. And your relationship with your friend is important and you do not want it to be weird between you. I guess it is a case of balancing those 2 things.

Do they have a long way to travel to your place? Is is likely that he would even be interested? Could you sus it out with your friend first before you do the 'official' invite? Could you tell her that you don't want it to be a huge event (whether that is true or not) and are trying to contain the numbers?

If she assumes that the invite includes her partner, would you want to risk hurting her by saying that he isn't invited? Would she be hurt if he wasn't invited? What is going to affect you more in the long term - his having attended the b'day OR a (possible) strain in the relationship with your friend? Only you can answer that one.

I guess the only definite is the fact that you don't want him there. At this stage, it is only hypothetical that she would be offended if he wasn't invited....

I hope that helps in some small way! Good luck!