2 who goes with open relationship, that should expect for it. but we can say, he was enough humanity to go for open relationship, not like the real cheaters, Sage, Maya, Jojo, Balla, Oscar, Oscar girlfriend, Chad
Slight derailment, but wanted to quickly comment on this. Having known people in consensual non-monogamous relationships, my perspective is that Tommy is just as much a cheater.
In all of the cases you listed, what makes the act immoral is not explicitly that they slept with other people, but that they broke the implicit/explicit agreement of their relationship. For the "real cheaters" you listed, there was an expectation or agreement of monogamy that was broken, and the breaking of that agreement is what actually makes it immoral.
As you mentioned, Tommy is in an "open" relationship, but that doesn't imply it's a free-for-all. In fact, there's an explicit agreement that before either partner has sex with someone outside the relationship, they discuss and agree on it. Tommy has broken that agreement multiple times, which is just as much a breach of trust as for the others you listed and demonstrates a lack of respect for his relationship and Heather, especially since he knows it upsets her. This makes him just as much of a "cheater". Worse, unlike many of the others, he doesn't seem to show any remorse for his actions.
If Tommy can't or doesn't want to abide by the terms of his relationship or if he's unhappy in his relationship, he should man up and discuss it with Heather. Either they agree to change their relationship agreement, or they break it off so they can pursue relationships that fit them better.
P.S. Regarding him slapping Heather at the table: there's a fundamental difference between consensual slaps and things like it during sex and the clearly unwanted slaps in that scene. The latter is violence, if not abuse.
