Dear Bel,. I've been married for 20 years – and I'm the long-suffering wife who's had enough of the suffering now. My husband has consistently been unfaithful to me over the past eight years. I'm now asking whether there's a point to staying with him, especially as he has now moved into the spare room so we very rarely sleep together. I do wonder if my forgiving attitude has almost conditioned him into his repeatedly bad behaviour.

His pattern is always the same: he meets someone on a chat line, or dating site, arranges to meet them, at some point sex occurs, and then when his object of desire starts to want more commitment, he moves on to the next one. My forgiveness is rooted in my strong faith. I've made all the excuses for him –sad early life, mother who rejected him, sexual identity problems, poor self-image, ego that needs constant bolstering. However, I've come to the point of asking can he really change or (more importantly) does he want to?.

I think we've all met that needy person we feel we can help, and offer all our energy and effort into solving their problems – only to realise they revel in the attention their problems attract. My Christian beliefs make me want to forgive and forget and to help my husband. I have so much to give yet I feel rejected, worthless and unloved. My friends tell me I'm attractive, sexy, intelligent and friendly and assure me that I will find someone who deserves my love. It's so confusing as there are glimmers of hope in our relationship: treasured moments away from the worries and frustrations of family life (we have three children) most recently on a lovely long weekend in France.

My question is really, how do I uphold my belief in my sacred marriage vows yet not live a lie? My love for him seems to have no effect. I feel I must give him the opportunity to turn away from the life that's really making him very unhappy and change for the better. But I need to seem strong, not weak. Do I just strike out now myself (as basically we are more or less separated) and find happiness for myself and forget my marriage vows?.

He says it is possible to give up his addiction to affairs like he gave up smoking. But they're hardly the same thing, are they? I'd love to know what you think. I most certainly wouldn't like any man to put me on the same level as a filter tip – and feel sad for you that this one can still (it seems) light your life like the strike of a match. You clearly love your husband no matter how often he has cheated and lied and humiliated you so much that you feel 'rejected, worthless and unloved'.

You live in hope that the tenderness you still sometimes experience (for example on the recent trip to France) might become the norm once again. It's quite extraordinary that you first claim stoutly to have 'had enough of the suffering now', then go on to prove that's far from the truth. You tell me you are 'more or less separated' (presumably because of the sleeping arrangement) then demonstrate, in every word, how much your heart and soul are still with your husband, even if your head is saying 'No'.

This marriage is not yet over, although for a majority of women (I suspect) the serial infidelities would have served his eviction notice a long time ago. The fact that you are a devout Christian who believes in the forgiveness of sins commanded by Jesus is both moving and exasperating. You cling to those sacred vows like a drowning person clutching a life raft – and in that behaviour you don't display foolishness (though many will think so) but the kind of fragile beauty that encapsulates all that's best about humanity.

Jesus taught, 'if you forgive others their trespasses, your heavenly Father will also forgive you' – and I for one have, at times, made that a way of life, even if it's painful. Yet it's exasperating that you can write 'I must give him the opportunity to turn away from the life that's really making him very unhappy and change for the better'. Isn't that exactly what you've been doing all these years?.

He's had plenty of chances but why should he stop philandering when he enjoys it? What evidence is there that it's 'making him very unhappy'? That he butters you up by saying so?. Your wishful thinking credits him with finer thoughts and feelings I doubt he has. This is a man who has broken his own wedding vows time and time again and (do be honest) shows little, or no, remorse. You have three children, and should certainly try to be strong for their sake.

As they grow older it will do them no good at all to see their mother reduced to a damp doormat. It's pretty obvious to me that counselling would be good for you both, but to get him to agree you'll have to play hardball. Since you love him, it ought to be worth it. I think you need to tell him that you will seek a judicial separation unless he agrees to try to mend the marriage. Suggest he starts looking for a flat to rent in the meantime. You need to be very cool and calm but really determined – a note in your voice he probably hasn't heard before. Do it.