元彼のインスタは、なぜか気になってつい見てしまうって英語でなんて言うの？

I don't know why - you have no reason for checking it or you can't explain why you check it. When you find yourself doing something, it normally means you do it without thinking, it is just something you do automatically. Feel the need to - something makes you want to check the account but you may not have a reason why.

▪For some reason I end up checking my ex boyfriends instagram. Reason=a cause ▪I have no idea why I am stalking my ex boyfriends instagram. Stalk=obsessive attention

The important thing here is why you are looking at your boyfriend's Instragram. Does he know about it? If you are a jealous or worried your boyfriend may be two-timing you, then it is understandable that you check sometimes - but it may cause some serious problems if he finds out! Or maybe, he lets you look and is fine with that? To two time = deceive or be unfaithful to (a lover or spouse). "He was two-timing his fiancée back in England."

When you are making a statement in a casual conversation you might be having with a friend, or you were asked the question if you check your ex-boyfriend's Instagram, you can use the first two sentences. The reason for you checking his account can be because you are still heart broken over the fact that you two split up or because you just want to find out what he is doing. If you want to state that you are still heart broken and still want to know what he is doing or if he is seeing someone else, then you can use the third sentence. hung up - heart broken (synonym - different English words but can have the same meaning)

When you want to explain that for some reason you still check your ex-boyfriend's Instagram page, then you may express this in the following ways: -I still check my ex-boyfriend's Instagram -For some reason, I still check my ex's Instagram

These sentences imply that one likes to check/see their ex's Instagram and they are unsure why. the term 'Ex' is given to the person(s) who you have had previous relationships with. To 'check' something is to see/look at and investigate something in particular, in this case their ex's Instagram profile.