During the exclusive phase she never fought and was always on her best, most positive behaviour.

I’m reading this to mean that you were exclusive before becoming a committed relationship. And that she was treating you better before you officially committed.

Not gonna lie man, this sounds pretty bad. Essentially the moment she got the relationship she became a pain in the ass.

Are your fights always in the realm of jealousy/your past player life/other women? I think you two are probably cooked either way, but if it is just one extra huge comfort test, you can always word it something like “Babe, you know how I used to be. I chose to quit that life to be with you, so I don’t want you to worry.” And hopefully that is actually a true statement for you.

———

Here's the thing: she's a genuinely great partner. Low body count, treats me well, doesn't demand constant dates or attention, and she's peaceful and fun to be around.

This may have been true before, but it’s becoming less true by the week, from the rest of your post.

———

Can I realistically keep flirting and approaching while in an LTR, or do I need to pick a lane?

I’m certainly not the arbiter of how to behave in a relationship, but this mentality sounds dubious at best. You can probably get away with a little of this to maintain passive dread, but if continuing to flirt and approach new girls is important to you, why did you agree to be in a relationship in the first place? Seems like trying to have and eat your cake.

About 1.5 months ago I got into an LTR

No, you got into a relationship. It's not long term yet. A Long Term Relationship is measured in years, not months. It might become an LTR later, but it isn't one yet.

Since making it official, we've been fighting weekly over small things

Next!

1)She broke up with me for a few hours

Next!

she's a genuinely great partner

A) does not compute with what you've already said.

B) lol "partner".

she's peaceful

What?! Peaceful, but starts fights all the time?!

I want to actually give a monogamous LTR a real shot

Did you ever read the sidebar?

From probably the most important post on it, HumanSockPuppet’s Guide to Managing Your Bitches:

2) A long-term relationship CANNOT be your end goal. You can only be OPEN to the possibility of having one.

Men are the gatekeepers of relationships. Since a relationship is what you have to offer, you mustn’t just give it away. It must be a reward she earns in small doses for inspiring your trust and devotion.

I understand that many of you want a LTR with a good girl – sometimes a series of flings isn’t enough to fulfill you. Believe me, I sympathize.

But winning a LTR is HER problem, not yours. Handing a girl your devotion won’t magically make her worthy of it. When you WANT a LTR too badly, you place your focus on the idea of having a relationship instead of evaluating the girl. You become fixated on your fantasy relationship and selectively ignore the things happening right in front of you: her deep character flaws, her indiscretions, and the red flags.

You must regard women as candidates applying for the job of being your girlfriend – a supporter, a lover, a comfort away from the everyday battles. Don't just hire a bitch because you want the position filled. Make sure you vet your candidates fiercely and hire the right girl for the job.

Can I realistically keep flirting and approaching while in an LTR, or do I need to pick a lane?

Again, you aren't in an LTR yet, but speaking as a dude who's been married 21 years: it greatly benefits you to keep your skills sharp with other women. The preselection helps keep your woman attracted to you. You don't lose your edge. It keeps your confidence up when you know you have other options.

You can handle it better. If she gives you grief, just say something like "I can't help it if I'm charming!"

But this woman sounds like someone not to keep around.

Some context first. I've been spinning plates for the past couple of years. About 1.5 months ago I got into an LTR with a girl I'd been exclusive with for a few months before that. During the exclusive phase she never fought and was always on her best, most positive behaviour.

Since making it official, we've been fighting weekly over small things. Examples:

1)She broke up with me for a few hours because she thought I didn't find her pretty. 2)Yesterday a bitch left a flirty comment on my Instagram post. She assumed I was entertaining other women in my DMs and micro-cheating on her and called me.

Instead of ending things that time, she in a mature tone offered to go back to being non-exclusive. She said she'd be fine with me sleeping with other women, we'd keep hanging out like nothing changed, and her feelings and expectations would just be "better managed." I was caught off guard and hesitated before answering, which I know was a mistake. I eventually reassured her and calmed things down.

She knows about my past, and I think that's the root of it. She's worried I'll get bored and go back to that lifestyle.

Here's the thing: she's a genuinely great partner. Low body count, treats me well, doesn't demand constant dates or attention, and she's peaceful and fun to be around. Honestly, she's low-maintenance compared to managing multiple women. I'm not usually the reassuring type, but I'm enjoying monogamy with her and I'm not in my plate-spinning phase right now. I want to actually give a monogamous LTR a real shot.

At the same time, I see the appeal of the other side. I still want to flirt, talk to bitches on Insta, cold approach, and so on and thats a fun lifestyle not gonna lie

So I'm stuck:

How do I handle her insecurity without becoming her full-time reassurance machine? Was her non-exclusive offer a genuine option or a shit test? Can I realistically keep flirting and approaching while in an LTR, or do I need to pick a lane?