I hate what dating has become. Clicking a button on social media is now a point of contention and everyone is insecure, I'm even guilty of this in previous years. It's a major issue in culture right now and this type of stuff is all too familiar to a lot of people.

Is he not showing you an appropriate level of affection? What if the pictures he liked weren't of his exes but of strangers with similar 'sexy' selfies, would you still feel the same? I can't defend what he's doing because I do the no contact, cut social media deal with mine, our breakups are real breakups for the most part, I can find new friends that didn't give me a reason to not be around them. Was he dumped by them, the breakup amicable, or was he the decider of ending things.

Ultimately, this is on you and your self-confidence, whether or not you want to continue. Own yourself. Maybe sit him down and say to him that you don't feel the action of liking a woman's picture on social media is what bothers you, if these women were random, ok, I can understand someone acknowledging beauty, everyone can be beautiful, but that these women come with history in his life and that you aren't comfortable with that. Maybe that will get it through his head, because a self-actualized and mature human would not do what he's doing while in a relationship. I would also consider not paying as much attention to social media in general, a lot of this over-dwelling happens when people are bored and overthinking.