And a source tells PEOPLE that Rodriguez, 45, "was pretty surprised," himself when he heard about Affleck, who was seen at Lopez's home in Los Angeles in late April over a week before the actor, 48, and the singer, 51, went away together for a days-long trip to Montana.
"Alex is not thrilled," the source says of how things have recently unfolded after his split from ex-fiancée Lopez, noting that former New York Yankee Rodriguez had hoped things between the pair would remain amicable.
"It definitely hurt his ego," the source adds of Rodriguez's reaction to Affleck and Lopez spending time together 17 years after the pair broke off their own engagement in 2004.
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"[Alex] was under the impression that he and Jennifer would go on as friends, but he is acting so needy that Jennifer cut him off," the source says of Rodriguez, who recently told photographers "Go Yankees" when asked about Lopez and Affleck, who is a longtime Boston Red Sox fan.
"Jennifer seems very happy. She tried for a long time to get her relationship with Alex to work. She feels good that she decided to break it off. She just doesn't trust him and didn't want to waste any more time," the source concludes.
In April, Lopez and Rodriguez — who got engaged in March 2019 after two years of dating — confirmed their breakup with a joint statement. "We have realized we are better as friends and look forward to remaining so. We will continue to work together and support each other on our shared businesses and projects. We wish the best for each other and one another's children. Out of respect for them, the only other comment we have is to say is thank you to everyone who has sent kind words and support," their statement read.
A week after the statement was released, a source told PEOPLE it was Lopez who ultimately broke up with Rodriguez. "She insisted on it. There are too many issues that are unresolved," the source said at the time, adding that the mother of two could no longer fully "trust" Rodriguez, who flew to visit her in the Dominican Republic to make it work days after they publicly acknowledged on March 15 they were working through long-simmering issues.
Shortly after, Lopez and Affleck, who was dating actress Ana de Armas before splitting in January, were pictured spending time together at her L.A. home. "They have a lot of love for each other. They have always admired each other," a source previously told PEOPLE of Lopez and Affleck as an insider similarly said: "They are friends. They have always been friends and they have seen each other through the years."
And this week, a Latin music insider told PEOPLE that the right timing may have brought Lopez and Affleck together again after over a decade apart. "Ben and Jennifer were in the same mindset after their breakups," the source said. "Whether they end up together or not it's good for both of them now. And not that surprising."