Sean Evans‘ ex, Melissa Stratton, says he dumped her once the world caught wind that he was dating a porn star — something she says he was cool with at first … but changed his mind later on.

We talked to the model/adult film actress Friday in L.A. just ahead of a podcast she was heading into at the No Jumper store — more on that later — and our photog chopped it up with her to get the story on what exactly happened between her and the “Hot Ones” host … who’s quite private.

According to Melissa … things were going swimmingly between her and Sean for at least a couple months, and she says they were having a great time together as a new couple.

We even asked her about the Super Bowl — where she was posting tons of pics of him that weekend — and MS says they were actually going around introducing each other to friends at that point … which makes the split all the more sucky, ’cause she says she liked him.

As for why things fell apart … Melissa says her work in the porn biz was ultimately to blame — and more specifically, how her being in that industry would affect his image.

The way she tells it … he had a little bit of a flip-flop in opinion over whether he was actually okay with her past and current line of work. Melissa claims he was on board at the beginning — but suggests that once their relationship fell into the public eye … he got skittish, which she gets and has no hard feelings about.

Sean, of course, hasn’t said crap about it all … and his team hasn’t gotten back to us either.

The good news for Melissa … business has been booming for her, and she says she’s happy about that. As for this pod she was heading into … it’s with Adam22, so that’ll air soon.