How do I address this?

My straight friend (31) and I (30) have been close friends for a good decade. He’s also in a relationship for 15 years, high school sweethearts and all.

He’s aware that I’m gay because our mutual friend (closeted gay) outed me during a get together last year.

I’ve also noticed that he’s been overtly flirtatious with me but I just assumed that he’s just secured with his sexuality. To add too that, when he’s drunk, he gets super touchy with me, regardless if he’s hanging out with me or out with our group of friends. He also likes to call me drunk when he’s with his girlfriend and his own group of friends, under the influence. I’ve just brushed and laughed it off thinking it was joke.

Also, he’s been hanging out at my place almost everyday, to the point where I even questioned if everything is okay with his relationship.

His girlfriend even messaged me a few days ago, saying that I’m home wrecker. I’m so confused, how do I bring this up?

I also have a screenshot of what his girlfriend dm’d me on IG but I couldn’t post it here along with this question.

Edit:

I’m just going to copy and paste what his girlfriend dm’d me on IG.

“I've been over hearing what Michael has been saying to you over FaceTime/phone calls, everyday. And the fact that he's been coming over to your place almost everyday makes me feel extremely uncomfortable.

Ever since you've been outed, l've been hearing some ludicrous shit with his phone calls like "I'm going to shove my cock down your throat" and "I'm going to massage your insides with my cock". Which justifies me sending this messages to you. All you do is brush or laugh it off like it’s some joke, don’t take it too lightly, he’s only touchy with you when we’re out as a group and I just can’t fucking understand why he pays so much attention to you.

He's probably been doing that with you whenever he goes to your place, huh? Massaging your fucking insides with his cock.

He's been so distant and doesn't even touch me anymore. When I first met you and over the course of knowing you for 10 years, I thought you were a great, chill, and wholesome guy. But I thought wrong. You’re just a fucking home wrecking man whore, go fuck yourself.”

She literally crashed out in my dm out of nowhere. We literally just game at my place and we also have other friends that come by my place sometimes, im so confused lol.

Edit 2:

So, he slept on my couch last night, anyways, this morning I showed him what his girlfriend said to me and his reaction was livid.

He apologized for getting me roped into this situation and briefly explained that she’s been super controlling the past few years and that she’s been asking him to choose between her or me. He left after that explanation, so I don’t know what’s happening now.

I was, also, planning on setting some boundaries too, but that can wait until their shit gets sorted out.