Why would this girl from work only start inviting me out now that she's got a boyfriend?

We've worked together for a few years and we get along great but its never carried into activities outside the workplace, over the past few months she acquired a boyfriend and from what I know I believe they've been together now for 7/8 months - but now more and more often she invites me and my SO for double dates and to different events.

Curious if there is something a miss here her new guy is great but why all sudden this far into the relationship am I just meeting this guy and getting these invites that I never got in previous years when she was single (to hangout I mean)?

Why would this girl from work only start inviting me out now that she's got a boyfriend?
Post Opinion