dont know if it helps but I guess if the ex had an affair you might be saying that there was behaviour leading up to that that was unreasonable - being cold/unsympathetic hurting your feelings by belittling you, failing to show intimacy, if you pin those to particular events/dates?
Alternatively why are you not filing for adultery if thats what happened - newbie to all this and not an expert/professional in this field so there may be good reasons for that. If your ex doesn't care about what you put then you can be as vauge as you like I guess.
Hope that helps.
Last edit: 21 May 20 by Trailsloth. Reason: second thoughts to add
Thanks for your help. I understood that with adultery you have to send papers to the person they had the affair with (i have no idea of their personal details) and also you have to prove they had sex - how to prove that I have no idea!!
Unless you have a written admission from your spouse or hard proof such as photographic evidence of the act, or an established pregnancy or child as a result of the affair, it is best avoid using adultery. If the respondent refutes the adultery you would have to amend your petition to behaviour.
You don't have to have the petition served on the third party unless you have named them as a co respondent. Not a good idea to do so as you will then also be relying on their admittance of adultery. They would also be named on your Decree Absolute.
You can cite that the respondent had an inappropriate relationship with a third party as one of your behaviour examples.