I had a similar thing happen to me - BF is 20 yrs older than me and we started as an office romance. Prior to our "coming out" as a couple, he was the only male in the office besides our boss and all the women fawned over him. Which was the main reason for our trying to keep quiet about dating
... I sensed there would be drama if we "took that away from them"... well, it inevitably came out and one woman in the office (married, by the way) who is closer to BF's age initially "supported" us... but after a couple weeks she came to me and said, "Scarlet, I heard that a young man over in such-and-such office thinks you're cute... I could set you up if you wanted..." I was speechless at first... and very offended. Mainly because it seemed that she really didn't think BF and I were for real...
I simply replied to her "No, thank you... I don't think BF would appreciate that."
She was always meddling... until finally both me and BF got jobs in other offices (not because of her, we got promotions
Having experienced it myself, I don't doubt at all that Stepmom doesn't approve of your relationship
and is trying to show that.. Call my a cynic... but that's just my little ol' opinion.