Yeah.
You weren't "too emotional" - by too emotional he means you looked like you might dump him, he thought there was a good chance he'd get dumped.
When you believed the lies, continued the relationship and got engaged; he knew you were locked in and extremely unlikely to dump him, so he felt confident & comfortable enough to confess to the years of being on dating sites. I think he's still lying about doing absolutely nothing on them though.
Nice wag of blaming you for him lying to your face too. No, it's his responsibility entirely for choosing to lie to your face back then. Were you supposed to be all chilled? Would he have been all chilled in reverse circumstances? Would he, fuck.
Anyway, he - at the very least - cruises dating sites and is a liar. Hell lie to your face to get himself off the hook and then fess up a little but when he thinks you're locked in .... Like you would be later with kids.
That's not marriage material.
He's shown you he's not marriage material.
Don't fall into sunken costs fallacy because it's 7 years.
The 7 years only goes to prove he's been acting like this long-term, so I'd imagine he'll continue acting like this.
You know the person who showed you his tinder profile is hoping you end the relationship and don't marry him, and anyone else who knows too. You know what they must think of him and what a farce he's made of your relationship. They're hoping you won't continue being his stooge and victim.
Oh and the lying to stop you from ending the relationship when you first found out - he'll spin at as loving you so much. That's not true. He wouldn't act the way he has been if he loved you ...and was capable of decent, fair, respectful love.
And cheaters always lie or manoeuver to get back in control when they're caught.
They think they're in control of the situation when they have you as their main secure partner, while they look and dabble elsewhere. They don't want to lose that. They'll say and anything to get back that control, not to be on the wrong end of the stick .... Being dumped and left truly single if/when they don't want to be.
They don't want you to do the dumping; they want to do any dumping that's done - if and when it suits them.
They'll say whatever they need to to get back in that secure position... And then revert to their cruising/dabbling/looking for options/side action.
And believe me, if they thought they'd gotten something secure with someone they perceived as "better' than you, they could well be outta there.
Even if they don't leave you, some men are always wanting main chick and side chicks/side action. They think it's natural and they think they're entitled to that.
They don't think women are entitled though. That's why he"'s felt entitled to be on dating site for "confidence boosting" (hmm) for years while he "forgot" to tell you, and let you have the option of doing the same.
There is also the old "I cheated/tried to.cheat because my self esteem is low, boo hoo!!".
Nah, if your self esteem was low wouldn't you be thankful, grateful and scared to lose what you've got ...instead you're looking for more/extra/something else. It's not low self esteem, it's greed, sly-ness and entitlement and double standards.
Would self esteem and confidence boosting be an excuse he'd accept from you if he found out you were on dating sites behind his back for years??!!
You'd be called all the names of the day, he wouldn't trust you, and I seriously doubt you'd be getting married.
This is not a good background to a marriage or a good person to marry. He's a type of cheater (whether he ever messaged people or met people ...which you'll never know without evidence) and he's a liar and he thinks he's entitled to look around for others and advertise himself behind his partner's back
A broken engagement is cheaper and less painful than a divorce and a broken home (especially with little kids involved).