husband texts his female coworker constantly, am i overreacting?

i think the thing you can't explain is worth sitting with rather than rushing past. it's not really about whether something's 'going on' - you already said you don't think it is. it's more that the emotional texture of that friendship, the ease, the daily rhythm of it, is happening somewhere you're not, and it's landing in a place that used to feel like yours. that's a quieter kind of question: not 'is he cheating' but 'where do i fit in the picture of his day.' so maybe don't open with the coworker at all. open with that - tell him you've noticed you're not getting much of his 'lol you won't believe this' energy lately, and you miss it. see what he does with that. if he gets defensive, that tells you something. if he's just surprised and adjusts, that tells you something else. you're not asking him to draw a line for her. you're asking where you land relative to it.

you're not overreacting, you're noticing something real and that counts for a lot. the fact that he's not hiding it actually helps you here, it means this is a conversation you can have without it turning into a whole investigation. lead with the feeling, not the accusation. something like "hey i've noticed you and [name] text a ton, more than us some days, and i'm not saying anything's happening but it's been bugging me and i want to talk about it." that's it. no ambush, no evidence pile. then ask him directly what he thinks the line is, because you're right, everyone's line is different and you two just haven't compared notes on yours yet. that's a totally normal married-person conversation, not a jealous one. worst case he gets defensive for a sec, best case you find out it's genuinely nothing and you both feel closer for talking it through. either way you'll know more than you do now, and that's the goal here.

You're not overreacting. Volume matters, even without secrecy. Something can be completely innocent and still not sit right with you, and that's worth saying out loud. Here's the thing though: he probably doesn't see it as a big deal, which is exactly why you're stuck. In his head it's like texting a buddy. In yours, it's taking up space that feels like it should be yours. Skip the "why do you text her so much" opener, that lands as an accusation even when it isn't one. Try: "I noticed I feel weird about how much you two text, and I want to figure out why, help me think it through." That's honest and it invites him in instead of putting him on defense. Then actually ask what the friendship means to him, and tell him what closeness with you should feel like. You're not drawing a legal line, you're comparing notes on what feels normal. That conversation, done calmly, usually gets further than either silence or an ultimatum.