Greetings gentlemen.

First, excuse me if my language skill is lacking. My English is a little rusty.

TL;DR

At the party I overreacted (was drunk) and approached a man flirting (supposedly, they were talking alone for some time) with my wife and told him to GTFO. Pushed him with the shoulder, pretty close to physical escalation. In the morning felt pretty beta about it but hold the frame and told the wife I am old fashioned and she needs to keep herself in check in such situations. VERY emotional sex afterwards, to my suprise.

Background:

Married 5y+, 10+ LTR. I'm unplugging after years of being a bitch, found MRP 3 months ago so still a newb. Lot to do, but I see massive progress because I started lifting year+ ago (prior to finding MRP). Had some hits and misses with wife recently, but I see improvement in sex (didn't go as far as dead bedroom though, once a week at worst) and her behavior. I'm past WISNIFG and NMMNG, reading Practical Female Psychology. Lifting rather consistently and progressing. Work is good. Upgraded my hygiene, style and wardrobe massively. Owning more and more in my life, wife being less and less responsible. After few weeks of intense shit testing she started to respond pretty well.

On with the topic:

Me and wife were at a pretty wild closed party - 20+ people, we know everyone rather well. LOTS of booze, great atmosphere, having lots of fun. I love to dance so I had a good time with few girls on the dancefloor. Wife didn't want to dance for some reason, that was weird but I just approached other women. Not paying too much attention to wife, just hanging out with people, drinking a lot, dancing, etc. Late at night, pretty buzzed, I see wife is talking to a guy that is new in our social circle. I feel slightly uncomfortable somehow, but ignore it and go about my own business. Some time later another guy tells me that he saw them talking for a long time and it seems 'inappropriate'. Right then I was really bashed and couldn't ignore it. Bloke was probably similar SMV to me (pretty fit and attractive). The guy eventually went to a dance floor so I grabbed him and took him outside. Told him that I didn't like how he was talking to my wife like that. Didn't pay attention to what he said, just locked eye contact until he broke it. Told him to get the fuck out of the party, he ignored it. He kept hanging around, but didn't approach wife anymore.
Wife was probably unaware completely about this.
Later we were leaving late taking care of my friend who had too much booze. At the way to the exit I saw 'the guy' in the corridor, and pushed him with the shoulder pretty hard, he almost fell. I act 'badass' and just keep walking with my stoned friend. Behind me the guy supposedly wanted to follow, but wife tells him not to try it. We get home and don't talk a lot about that other than I told her I didn't like that they were walking for so long.

I wake up with massive hangover. Thinking back about what happened I fell like a butthurt bitch. I see my actions as a way to tell my wife she is very sexy (she was #1 or #2 girl at the party) and worth fighting for, and I am an insecure faggot. I suck it up, call her and we snuggle a bit. We talk a little about the party, what we liked, what was fun. Eventually, we talk about the situation. I just tell her she should keep herself in check and that was inappropriate. Of course she tells that it was all innocent (and it probably was), I say I know but at the time I didn't care about being rational. I look her in the eyes and say 'I didn't even know I will have to fight for you one day' smirking. I see THE SPARK in her eyes. I can feel it, the tingles, they shower all over her. We kiss, and it was THE KISS. I sex her, and she shivers, writhes, smiles, relaxed. Looks back into my eyes and I see THE SPARK. I haven't seen it in so many years... Before I come I tell her 'I will do so many dirty things with you...', she responds 'one day...' and smiles. It was a lovely morning.

Later I told her I will talk to the guy. I set up meeting and talk with him about that. I don't apologise, just say I don't want any hard feelings between us. He responds with some bullshit that he didn't feel that was inappropriate what he did, but respects me that I escalated when I stopped liking it. It ends on generally positive note.

Conclusion:

I was pleasantly suprised how Wife reacted to mate guarding. I feel I could have handled it better, but it seems it isn't always so bad. At future parties I plan not to give a fuck and just continue to twirl blondes at the dance floor should someone hit on her. But I expect she will be more cautious.