There are a number of useful strategies but I have found that a couple are extremely effective.
1) Tell her that you have a terminal disease, albeit it a very cosmetic one, and that it would never be fair on her to watch as you fade away from life. Nor should she be conemmed to spend her time and youth visiting you, comforting or caring for you. No, far better - for her - that she makes a new life, finds healthier and better friends and lets love return to her. The advantage of this ploy is that she will be grateful, and consider you to be a fantastic bloke.
2) Tell her your wife now knows and is homicidal, however, should she ( the bit of fluff) wish, you will leave the wife, bring all the kids, dogs and ferrets and move in with her. Of course, since you work for your father-in-law, you will now be unemployed and unemplyable. But you are sure that she can keep you.
3)Tell her that you have decided to come out of the closet and admit that being gay is the only way of life that will suit you.
I suggest hitting her over the head with something heavy, (a Wok may do) and chuck her in a wheelie bin. Fill the said bin with cement and push to the nearest bit of deep water under the cover of darkness and push her in.
Do what I do, be polite when he calls round, wear skimpy clothes and when he tries it on, tell him to go see his new girlfriend for a sucking. Then as time goes on and he still conitnutes to pop around to check you are ok, shag him sensless, pat him on the head and send him on his way, but neglect to mention that your on the rag and the fact that his light blue jeans now have a lovely red mark all down the front.
I've found the most effective way to emasculate a man whilst retaining the moral highground is to tell him that you love him like a borther. This conveys the message that he is dull and antagonistic, has failed as a lover and has become a duty ****.
I had to do a runner from one bird in Kings Langley a few years ago. Sneaked into our (her) maisonette in the afternoon whilst she was at work, took all my gear out and laced the gussets of all her knickers with itching powder. Good job too as she found out I was humping her best friend just a few days later. Narrow escape that.
Best advice I can give is either have man no.2 in the wings waiting or a friendly male to commiserate with. Failing that stay away from any entanglements by becoming a workaholic or rediscover your friends. Give yourself some time to reflect and regroup and then get back in there.