Cohabitation

Hi
I have been happily divorced since 2001. Have 2 children 16 and 13 for whom I pay CSA with no issues. My question is this.
In the court order I am pay spousal maintenance (and have done since divorce) but it states that I do this until my ex wife either:
1. Dies
2. Cohabits for a continuous period of 6 months
3. Remarries
4. Until further order
I believe she is cohabiting and has been for about 2 years + (His vehicle is regulary at her address. When I have telephoned he has answered and on one occasion neither my ex or children were there and he said he had 'just popped round'. Short of her admitting it (which she doesn't) how can I prove this and what level of intelligence/information regarding cohabitation does a court require. I will not involve the children in acting as witnesses.
Regards

Is he registered on the electoral register ? In the phone book ?
would neighbours verify he resides there ?
Tets

Thanks for the reply.
Sadly he is neither registered with the council or DVLA and the neighbours are unlikely to be helpful.
I know he has been divorced and has children so perhaps he is in a similar position but that shouldn't mean I continue to pay just because they can't be honest. I have no issues with paying what is due and haven't had for the past 9 years but it really is grating when I 'know' he is living there but she simply won't admit it.
I have asked the court that issued the order what 'they' mean by cohabitation but they clearly can't be bothered to reply (its been 6 weeks). My search for an answer goes on.
Thanks

Hi all. An update to the 'cohabitation' issue. I contacted the court that issued the rule regarding my ex wife cohabiting in respect of the spousal maint. asking that they perhaps would like to add some clarity to what they meant. Sadly, the district judge has 'decline to comment'. It seems to me that before anyone else accepts such a clause to the spousal maint payments that they seek some definition of what the court means because afterwards it appears that unless your ex admits it and is 'honest' your likely to be paying it for many years to come!