Am I ignoring red flags? Part 2

The community helped me to realise we have a problem, I will try to fix it before giving this up, (Red Flags? Part 1) I would like to ask for more inspirations on this...

We have been together for 2.5, he (59,bi) has always been poly but was in mono marriage for 30yrs, and he is my first poly-boyfriend, I (40, F, flexible) have a lover whom I only see once a year.

We were busy with each other and life, so for the last 2.5 years, we were mostly monogamy, we go to play parties together and be with other people together, he saw less than 5 other individuals since we were together, generally while I am out of town. We mostly live together and share the same studio.

When we discuss boundaries, how we want to open up, I want a heads-up, when he starts seeing someone, going on dates, so I have time to digest there might be a potential significant one, aka I have time to deal the fear of threat. But we can't agree on the definition of "A Date or A friend"

Date: To him, having a drink without sex is not a date; if he brings someone back, not necessarily they will have sex, so that's still not a date; only if it turns out having sex, then that's a date/play time, so according to his no divination, no heads-up will be given.
There was also a time they did play, but he didn't tell me afterwards, and claimed he had told me they were flirting on text, and I am aware of the meetup, and I should assume nothing less.

Friends: everyone is a friend, with a sexual history or not. On the first few months of our relationship, he asked me if I am up for inviting some friends over for Christmas, “of course” I said. But then he was buying sexy lingerie for this friend, I got confused if it is appropriate? He then clarified, these friends are playmates, they have had sexy Christmas party for the last 2-3 years. I didn't know when I signed up for a Christmas dinner with friends, it means a sexy Christmas play. We discussed it, and I started to ask for clarification whenever he mentioned "friends"

The combination makes "I am going to meet some friends" very vague. I hate to ask for clarification everytime "by friends, you mean someone you may have sex (because he wouldn't call it a date anyway) or like a work friend? by meetup, you mean play time or a coffee in the public? " and still, work friends doesn't mean they didn't already have sex and won't have sex at all. 

I know if I am secure enough, even if he doesn't say anything, has sex all the time with anyone, I shouldn't be bothered, but I don't like the ambush. On the good days, I managed not to ask anything at all, but on bad days, I can't help to ask for more information, am I overeacting?