Get professional legal advice from a family law solicitor, asap- you've got your appointment booked- well done. Formalise your separation date. Make sure any joint named banking accounts, if you have any, are frozen until any agreements secured.
Communication: Be polite to ex husband at all times but don't be brow beaten or a soft touch- e.g. when he text you to say he would be filing for divorce whilst you were on holiday- thank him for his text and that you will be in touch once you are back home from your holiday to communicate further. Keep screenshots and copies of all written communication.
Suggest, in writing, to your husband that you would like to attend to attend formal mediation together, to discuss fair financial settlement proposals, with the assistance of a professional divorce mediator. Not expensive. If he refuses, keep evidence of his refusal, potentially to show in any future court proceedings. You will both be required to disclose financial income, outgoings, pensions, assets etc. You own rental home, so does he, so you both have rental income. You also both therefore have the means to adequately house yourselves the key issue is reaching agreement for a clean break settlement. Make sure you secure a clean break settlement.
Your biggest concern no doubt is the value of the house you purchased entirely with money gifted to YOU by YOUR parents, that you lived in together, not for many years, that is solely in your name. You have not indicated whether your parents gifted you that money whilst you were married or before.
Get all documentation together to demonstrate you alone purchased the home in your sole name. You "allowed" your husband to have benefit of living there whilst married, instead of living is his property purchased in his sole name, but he chose to end that "benefit" as he moved out. It may be that your parents gifted that money to you, solely for "your benefit" and expressly did not intend their gift to be considered a "marital asset" to be shared on divorce just a couple of years later?
If you feel able and can bear it, it may be beneficial to rent out that property and live temporally in your rental home or find somewhere else to live and pay rent, in the same way your husband has moved out. That way you are both in the same situation- ie he has property in his sole name and so do you. You can try to negotiate within the mediation process that you both agree to place no claim on each other's property that is in sole names. That way also you could say to your husband your parents gifted that money expressly for your "sole benefit" not as a "marital financial asset" which would be very hard if not impossible for him to prove.
Keep evidence of any financial support you've given your husband since separation- dates and amounts. Take that detail into mediation discussions/ legal process to remind your husband he has already had that benefit from YOUR financial assets- and can be fairly deducted from any agreed financial settlement.
As he has a rental property and adequate income I would suggest giving you ex husband no more money. The way he manages his State pension, work income and rental income is up to him- his money mismanagement, i.e. overdraft, is not your responsibility or concern.
You do not mention pension savings- i.e. occupational. You say your husband has already reached state pension age, still works and earns £1,000 a month but does he has an additional occupational pension? Have you reached state pension age? Do you still work and have an income. Do you already draw on or have yet to come an occupational pension? All to be considered.
You were married for a fairly short time, both have property to access in sole names and have no young dependent children have needs to be considered. That makes things more straightforward in many ways.
If you had drawn up a will with your husband- that needs to be changed, updated I would suggest- lawyer to advise.
All of that is transactional. Your emotional care is important Take good care of yourself emotionally- the breakdown of any marriage is not easy and takes its toll. Perhaps consider counselling- not relationship counselling but to help you navigate the separation and divorce process. Surround yourself with good friends, supportive loved ones.
Take good care Readandcook and good luck! 💐