However, a source close to 44-year-old Affleck disputes that the actor and Shookus got together while both were married, although the two were friendly.

The source says the two got romantic after his separation from Garner in 2015.

They had a ton of other problems." June 2015 -- Affleck and Garner separate Affleck and Garner announced their split on June 30, 2015."After much thought and careful consideration, we have made the difficult decision to divorce," the two said in their joint statement to ET.

"We go forward with love and friendship for one another and a commitment to co-parenting our children whose privacy we ask to be respected during this difficult time.

WATCH: 6 Things We Know About Ben Affleck's New Girlfriend Lindsay Shookus Let's take a look back at Affleck and Shookus' alleged relationship timeline. Interestingly enough, Garner made an appearance during Affleck's monologue at the time, to celebrate the actor hosting the show for the fifth time.

The two joked about Affleck's Best Picture acceptance speech for at the time.

At the time, he had been married to fellow dancer Clare Craze for six years, but they split that same year.

Striking up a romance with Karen, he married her two years later.

In pictures obtained by The Sun, Stuart and Karen have been spotted together on several occasions outside her home, with the duo leaving the house separately on Saturday morning.

It's claimed the starlet has enjoyed several meetings with Stuart, with sources claiming to the paper that the accountant is 'absolutely besotted' with Karen and is hopeful they will have a 'future' together, despite her still being married to Kevin.

According to the source, Affleck and Shookus were seeing one another as far back as late 2014, months before news broke that he had an alleged fling with his children's nanny, Christine Ouzounian.