i think he's lucky you're pretty open minded. rather than making this an issue maybe you can actually enhancing your sex life.

maybe brainstorm what you both can do to experience the thrill together. maybe if it's involving stranger then do some light exhibitionism together for a start.

ask your husband to do this.

if you know what time she's coming, ask your husband to wait with you in front of your apartment door, start to do a really hot PDA, hugging, kissing, grab his penis or ask him to grab your ass, make sure she can see. when she walked pass, stop for a bit and you say hi to her. and ask him to ignore her.

just make sure your son doesnt see what happened.

i think everyone will have different level of ok with this. luckily you understand how it feels so you don't get upset too much.

i think the ball is in your court. you can ask him to stop cos for most ppl that's cheating. or if both of you are open enough, you can start sexting random ppl too, be open to each other and use the sexual tension from that into your sex life.

just have sit down and talk about it.

there are discrepancies in your relationship. he gain weight and after living together you know he's a slob. but you don't mind those. for some ppl that's a negative changes.

i assume he doesn't like you're gaining weight but he never said anything because he gains weight too. and it's maybe true that he's becoming less attracted to you.

maybe have a sit down and try to get better together. you try to lose weight and you asked him not to be a slob and start helping out or he tries to lose weight as well. don't ask him to do both cos he will feel it's unfair. i think it's better to be someone that he wanted rather than policing his social media usage.

with the insta girls. personally i think it's hard to supervise that. those kind of stuff also appears in my feed and occasionally i look at them. im married and i know my wife dont have body like those models but im still masturbating to video of us having sex the most.

does he also gain weight during your relationship? if he does, are you ok with it?

or is there a change in him during the relationship that you don't like?

from my personal experience when someone is make a move or being flirty like that. i just said something that shows im happy sexually with my wife.

back then i got a female colleague who started talking about sexual topic in general and im pretty open to talk about it. when she started navigated the conversation to be more flirtatious and sexual, i just casually mentioned "i really love when my wife is on top, it feels so good i can't last." and normally ppl got the hint.