My boyfriend cheated on me early in our relationship

The first thing I would say is that if you do want the relationship to flourish, you’ll need to find a way of letting go of these resentments – and the worry that it could happen again. A relationship can’t survive unless the people involved trust each other and it sounds it’s that loss of trust that’s upset you as much as anything else. This, of course, is easier said than done in this kind of situation. 

There are a couple of things to consider here. The incident you describe happened four months into your relationship, which leads me to wonder whether you had different expectations of what you wanted from each other. Sometimes one of us falls in love or feels very close to a partner very quickly, while it takes the other person a while to feel the same. There can also be room for confusion when it comes to the ‘ground rules’ of a new relationship. For lots of people these rules include no playing away from home. And for others, they can mean seeing where things go, but not necessarily being exclusive. I’m not sure which was the case for you – although you do seem to be saying there was an expectation, at least from your side, that you wouldn’t be with anyone else.

You also say he tells you the reason he did it in the first place was because you were nagging him and the girl he found was easy going. If I were to take a really challenging position, I might ask: do you actually have a tendency to nag? I ask not to justify his actions in any way - even if what he said was true, cheating isn't an appropriate response - but because sometimes it's important to pause and think about how talk to a partner about getting our needs met. In counselling, we often see couples where one person is saying that their partner nags them all the time - but when we get right to the bottom of the problem it becomes clear that the nagging is just their way of showing the other half how unhappy they’re feeling. Not surprisingly though, when we keep saying the same thing in the same way over and over again, our partner might just switch off because all they think they hear is blame. And so - sometimes - they act out. Again, I mention this not to justify what he did, but to offer some chance of understanding it in context. 

That said, the ‘nagging’ defence can just be an excuse. It may be that your partner found any reasonable expression from you about what you need from the relationship just too overwhelming and so immediately decided to see it as nagging - and that he went with this girl simply because she didn’t ask anything of him, so it felt like far less effort than paying attention to your needs. This, of course, wouldn’t be a good sign – and if you do feel like this is the case, it’s worth considering whether this might still be his attitude.

Ultimately, only you can decide whether you’re able to put what’s happened behind you and move on. For what it’s worth, from my perspective you should forgive but not forget. I don’t mean that you should hold a grudge or let this eat away at you because doing either of these things has the power to destroy your relationship and you. Don’t let it. Instead you should be clear and honest that if something like this ever happens again the relationship will be over. Once you’ve made that clear, then you can get on with being a couple.

But a word of caution. You say you’re ‘always together’. This left me wondering if you find it difficult to let him out of your sight in case he does it again. I want to reiterate that any healthy relationship must be based on trust, rather than on constant checking. Don’t make the mistake, so often seen in counselling, of feeling that being in love and committed to each other means that you must be joined at the hip. Your relationship is more likely to stand a long term chance of success if you can be you and he can be himself as well as both being part of a couple.