Once you’re getting married you will have to put up with many ‘strange things’ ofhabits’ from your spouse. Once you get married you will have to put up with many ‘strange habits’ from your spouse.

Once you’re getting married you have to put up with many ‘strange things’ of your spouseyour spouse's many ‘strange attributes'. Once you’re married you have to put up with your spouse's many ‘strange attributes'.

It sounds more natural to reword the sentence to make spouse possessive, but the suggestion kiki0405 made also works. Also, I would recommend the word 'quirk' instead of 'strange things'. A quirk is a strange behavior, habit, or attribute. It has a mostly good connotation, so it's usually used to talk about the weird things that the people you like do. Instead of saying that your spouse has a lot of "strange" or "annoying" attributes/habits, you can just say that 'they have their quirks'. You would use it like this: "Once you're married, you have to put up with your spouse's many quirks."

Just remember the expression ‘to each their own’ and when you’ll finally come to terms with it, the marriage will be plain sailing. Just remember the expression ‘to each their own’ and when you finally come to terms with it, the marriage will be plain sailing.

Just remember the expression ‘to each their own’ and when you’ll finally come to terms with ithis, the marriage will be plain sailing. Just remember the expression ‘to each their own’ and when you finally come to terms with this, the marriage will be plain sailing.

"it" is ambiguous here because it could refer to either "the expression" or to "the marriage". It's not a big problem, but I would change it to "this".

That kind of unwritten rule has been around…let’s say…since Adam and Eve. That kind of unwritten rule has been around…let’s say…since Adam and Eve.

What you have written here is correct. Personally it feels more natural to me to say "has been around since... let's say... Adam and Eve."