Hello Rabbi, I have a question about yichud. I live in apartment that is connected through a locked door to my landlords house. A girl that I am seeing is having a issue; since her college closed due to coronavirus, she does not have a suitable place to study for her hard classes. I asked my landlord if I could keep the door open and designate him as a shomer who could come in at any time and he said he would do it. Would this be ok?

ב"ה Shalom, First even if the door is totally open to the landlord, we have to ask, if the landlord is a male and who else lives in his house. According to the Shulchan Aruch (Even Ha'ezer 25, 6) a woman may NOT be alone even with many men, unless the wife of the one men is there. The Rema there is bit more lenient and he says that a woman in a city maybe alone with two men of integrity. However, if their behavior is not modest a woman may not be alone even with 10 men. However, since you are both single even though the landlord is able to come in, it is not like an office where someone can come in unannounced at any time. I therefore adopt the opinion of the Nitiei Gavriel, (Dinei Yishud) chapter 33 that it is forbidden for the two of you to be in the same apartment. The idea of a shomer, to my understanding does not apply here. In addition, at night there is a need for 2 shomrim All the best