The dilemma Last year I found out that my husband of 20 years had been having an affair for a few months. It came as a terrible shock – I cried and cried for weeks. When asked to choose between her and me, he chose her and left me. I kept on crying. Two months after this revelation, I met someone and fell in love. This was a lifesaving event. Suddenly I could endure the pain of my husband’s betrayal. I felt alive and young again.

Now, my husband wants me back. He sees me happy and free from him, which of course is more attractive than a lamenting woman. He is still with his girlfriend and is probably worried to leave her in case I don’t take him back. I am torn. I’m happy with my new lover, especially sexually, but I also long for the relationship I had with my husband. He remains my best friend and we have so much in common.

I don’t know whether I can trust or make love to him again and I don’t know what his real motives are. Does he want me back because the grass isn’t greener or because he really loves me? But most importantly, I don’t know what I want. How do I find out?

Mariella replies So many choices. Before we start can I say how glad I am that you’re up for considering your own needs. What your husband wants, why he wants it and what he’ll do with it if he gets it is intriguing, but definitely not the most important thing.

I’m surprised you still describe him as your best friend. His behaviour falls way below the standard I’d expect of a good mate and as a spouse it’s even more disappointing. It’s very forgiving of you to regard his betrayal as more of a misdemeanour than a full stop, or you are making allowances he doesn’t deserve.

There’s no point in being naive – affairs happen and long relationships are guaranteed to come up against obstacles. As such, it’s a good idea to take the long view. But such seismic moments also offer the opportunity to reconsider your options. I’m not saying that what your husband has done is unforgivable – although many others might. Life is long and love is complicated, so taking an absolute position is unhelpful.

He’s given you a guilt-free chance to upgrade on romance in your life

Nevertheless, your letter contains a few jarring notes. You offer analysis of your husband’s possible motives in trying to reclaim you, but his approach also suggests he hasn’t learned his lesson. Having embarked on an affair behind your back he now appears to be deceiving his mistress – I doubt she is aware of his desire to be reunited with you. Either he’s a dangerously indecisive person or is so preoccupied with his own emotional needs that he’s entirely blind to everyone else’s.

In his current state of indulgence and confusion, he’s not to be relied upon, particularly as he’s still covering his options by remaining shacked up with his lover. What he has given you is a guilt-free second chance to upgrade or at least diversify in terms of your romantic choices.

There’s no knocking a 20-year marriage. It’s a wonderful foundation. But what you don’t offer me are mitigating circumstances. Sometimes, if a lover betrays us, we know all too well, deep down, how we have been complicit in their actions. Conversely, there are occasions when infidelity is just the final injustice heaped on an unfortunate partner’s shoulders. Which position is yours, I wonder? Was this a bolt from the blue in an otherwise happy life, or a near-inevitable progression after a period of unhappiness or stagnation?

Being brutally honest with yourself on all fronts is the only way to begin the process of decision-making. Were you blessedly happy or drifting apart? Did you live in each other’s pockets or lead separate lives? Rather than merely responding to his behavioural prompts, these are the questions you should be pondering.

Two months is relatively speedy to “fall in love” after the end of a 20-year relationship. It could be that you were just lucky and were ready for a change. But this current relationship might be a temporary act of self-medication. The challenges you face if you try to rekindle your marriage are immense as you will struggle not to be suspicious of his every move. But out on your own there are further hurdles, not least that so often we just repeat our old mistakes.

I’m interested by how little your new lover figures in your calculations, which suggests to me you may simply be rebounding. But this is not a binary choice between two men, it’s an opportunity to reshape your own future. You’ve been given a chance, however unwelcome, to rethink your life and I would be inclined to savour the moment. If your husband is serious about wanting to return, then making him wait will only increase that desire. Meanwhile, you need to do some hard thinking about whether someone who has betrayed you and left you bereft has really earned the right to a second chance. Whatever you decide, do it on your own time, not anyone else’s.

If you have a dilemma, send a brief email to mariella.frostrup@observer.co.uk. Follow her on Twitter @mariellaf1

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