Or is not really necessary? I mean in the situation where the relationship with your boyfriend/girlfriend is not very committed or formal but they had been dating for a while though and they are still young people (they are young adults) not wishing to get married like soon.
For example. I have a uncle who is married for the second time his current wife had alreayd 2 daughters from a previous relationship, many years ago. These daughters alrady had boyfriend each one for about 3 years probably. But now each time if in my family wants to invite our uncle and her wife only for a family gathering (coffee at home) just the 2 of them only (wife and husband), automatically we have to invite the daughters too and also the daughters will bring their respective boyfriend, as well. I mean is not even necessary to invite the daughters anyway, but when if we have to do it, the daughters will always bring theri bf`s. Not only that but our uncle himself ask us to invite the daughters too, even if in our plan the daughters are not included and not only that more plates cause the duaghters will bring theri boyfriend too.
In my family we know the daughters for some years, and we had invited them in the past, to some gatherings (not all) but when they did not have bf`s, now if we want to invite them, we have to count more plates cause they bring their bf`s. cause my uncle wants us to invite the ladies and the bf`s too. Today for instance my aunt invite me, my bro and mom and my odler sister and her husband to her house for a small family celebration, but my aunt never told us how many people she will be attending so we can collaborate for an approximate amount of appetizers. At the end she will invite her brother (my uncle) the wife, the wife daughters plus the daughters bf`s too. and not only that but my aunt is so stingy that she told my sister, she will hve the exact amoutn of food for each one attending no more no less and people cannot go for seconds.
