There is nothing fair about how we want to spend our time, lives, energy, and love; and rational has nothing to do with anything.

If you do not particularly like these people, cannot communicate with them or suspect they don't particularly like you, it looks to me like you have a couple of options. You can either decide it is not what you want to deal with and leave the relationship or you can decide to "wall off" that section of time and use it as a period when you can do what you want or need without having to consider anyone else, get a couple months free in your life to vacation, concentrate on your own work or projects, etc.

I would think it would depend on how you view your boyfriend and your relationship as to what you would choose to do. With my husband, he does not do things I do not approve of when I am not around so I would not have any problem with pretending he was "out of town"/the country for a period of time. I would not feel slighted or that his affections might slip or the relationship not be strong enough to take the separation.

If I were in the exact same situation as you though (but without the additional pot smoking; I still don't understand how getting stoned is good for business, how that works) I would be surprised that my husband did not include me because my husband enjoys me! My husband would have to literally be out of town or the country for our separation to work. I cannot imagine his being with anyone and enjoying that for so long. It sounds like a two month bachelor party and my husband would weary of that real quick.

I find it odd, too, that his business partner is here for that long and does not want to get out on his own, hasn't in all these years worked to learn English, doesn't have any sensitivity to his host's life the other 10 months that he doesn't offer to go elsewhere every now and then or the business doesn't pay to put him up elsewhere, etc.; these two men are both doing this deliberately, because it is what they want -- as you say, your boyfriend is not putting you first and it does not look like he has any intention of ever doing so. That would be a red flag for me. My husband and I put ourselves, each other, and the relationship first.

I feel your boyfriend is using you; you are convenient to him for ten months and he doesn't need you the other two. You fit in with his life or to heck with you (sounds like that's what happened with his marriage). Other people do not have to put us first; they should put themselves first but then comes the things they love and think of as "themselves". That he feels he can move you aside like a piece of furniture, roll you up like a rug, so he can bare the dance floor for his party. . .