Jennifer Lopez and Ben Affleck 'Didn't Want to Rush' Engagement: 'They Want to Make It Work' (Source)

Jennifer Lopez and Ben Affleck were not hasty about their engagement.

On Friday night, the Marry Me actress announced via her On the JLo newsletter that she and Affleck are engaged.

The soon-to-be husband and wife rekindled their romance last year. This new development in their relationship comes 18 years after they called off their previous engagement back in January 2004.

A source tells PEOPLE they are "both thrilled about the engagement" and that Lopez, 52, and Affleck, 49, "wanted to make sure this is it."

"Their relationship is different this time because they are older, more mature and able to deal with any obstacles," the source says. "They are both taking their relationship very seriously. They want to make it work no matter what."

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Lopez shares 14-year-old twins Emme and Max with ex-husband Marc Anthony, and Affleck has three kids with ex-wife Jennifer Garner: Violet, 16, Seraphina, 13, and Samuel, 10.

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Adds the insider, "They will not rush a wedding. They are content being engaged for now and aren't talking about any wedding details yet."

Lopez recently told PEOPLE what makes their connection different now compared to 18 years ago, saying, "We're older now, we're smarter, we have more experience, we're at different places in our lives, we have kids now, and we have to be very conscious of those things."

"It's a beautiful outcome that this has happened in this way at this time in our lives where we can really appreciate and celebrate each other and respect each other," she added. "We always did, but we have even more of an appreciation because we know that life can take you in different directions."

"We have been in the game in the public eye long enough to know who we are as people and what really matters and what doesn't matter. We have kids and we respect each other. ... We really live our lives in a way we can be proud of and our kids can be proud of you," she said. "We're just operating from a place of love and respect for everyone in our lives and that is very important to us. We know what the truth is [and] we hold it sacred."