I am in a romantic relationship with a very close friend of mine (we are both French and in the early 20s). We have been very close for years and we have been living together for a few months now. We spend almost all of our time together (nights and weekends).

When he visits his family who lives three hours away from our place, I am unsure whether I should come along or not. I came with him the last few times and it went well, I appreciate his family and I think it is reciprocal. However, I think it would perfectly reasonable if his family wanted to spend alone time with him.

My question is: How do I know whether his family would prefer me to come or not?

I would like to know because I would personally prefer not coming if it is what his family wants. They don't see him very often (once in a month or two months) and I don't want to "spoil" his visits. Also, in general, I hate being somewhere where people don't want me around.

My boyfriend wants me to come, and on his point of view his family has no reason to want alone time with him (but he's close to the description of Asperger Syndrome, and he may be missing some clues or something)

Giving that his visits are always informal, there is no proper invitation from his family: he just comes and they are happy with it.

It is a quite difficult topic to talk about since if he asks them honestly "Does it bother you if X comes with me?" , they can't really say "yes" because it wouldn't be polite and he might respond "OK, so we are not coming". I suggested him to phrase the question differently, like "Would you like to have alone time with me this weekend?" but he assures me that his family would take the question exactly as the previous one.

Is there a way to find out whether my presence is unwanted? Things to ask, or signs to spot when I am there?