Phelps and Rossee began dating at the beginning of 2012, according to reports, and the romance "started to heat up" just before the swimmer jetted off to the Olympics last month.
A source tells the website, "At the time when they began dating,
Doug Reinhardt was crushing on her too, but she chose to be with Michael instead.
"Michael knew that he had to leave for the Olympics and, not wanting to give up on their relationship, he flew Megan out to the trials in Omaha and then to London for the Games."
And now Phelps' final Olympics competitions are over, he is planning to take some time off and spend it with Rossee.
The source adds, "They'll remain in London for three weeks after the Olympics wrap up this weekend to check out the sights and do some traveling together."
Rossee is a former soccer player, who is currently a cocktail waitress at Blok nightclub in Hollywood.
According to her modeling profile, the aspiring catwalk star is a natural blonde with blue-green eyes.
In the profile, she writes, "I am super easy going and pretty much down for any type of project (that doesn't involve nudity). I love what I do."
