We all know that two's company and three's a crowd.
Normally, faced with that situation, we sensibly make ourselves scarce. But what if you are the gooseberry, not in the pub but in the office? So many architectural partnerships are also romantic pairings, frequently started in college. Two people who think so similarly about architecture are made for each other (and, anyway, they don't have the time to meet anybody else).
So after a few years in an apprenticeship with somebody famous, they set up in practice together.
And because they are talented and hardworking, they do well. Next comes the point when they need to recruit. What if the person they recruit is you? Suddenly you are an intruder, who does not know how the practice works, and does not understand their relationship either. There is only one rule: keep your head down. Remember you have been hired for your architectural skills, not as a relationship counsellor.
So when everything is going wrong between them, keep quiet. Don't offer advice unless it pertains only to work.
If you are lucky, they may leave some of their domestic issues at home. But work hard and learn as much as you can. Your chances of becoming a partner are slight and your job is pretty lonely. Use your time wisely, then land a job elsewhere where the professional is just a little less personal.