When I tried to talk to him about it he told me to take up a ceramic class or something to take up my time.
How did you feel when he stated that? "Sex life" has nothing to do with filling in time, it's about being intimate with your SOH.
I see two issues.
1) Time away and therefore you feel alone for the most part.
2) Non existent sex life.
You certainly should be independent and have hobbies and be your own person, I understand however, hardly ever seeing your Husband would make you feel that you are alone, 1 person not 2.
If I was you? I would "not" go to these two people's place for a 3 some. Doing something on the spur through frustration is not the answer to solving the above issues. You in addition, know nothing about these people what so ever, there is a reason why they started texting and texting and texting their own greed, to score . They could have engaged with 10's of people without protection in addition. They could be into bondage or things that shocks the shirt out of you and you want to run but can't get away, lots of danger signs there, yet, you are seeing a bit of "excitement". So in that, that is what you are missing from your life, speak to him AGAIN tell him perhaps of some fantasies you are having, desires you are having, make a move yourself, on, your, husband.