He cheated

If you think your partner is cheating on you, ask them. Be calm rather than aggressive.

Don't cheat on them just to start a fight, get revenge or make them jealous.

Don't fall into the trap of feeling like the loser in a competition just because they cheated on you, rather than you on them.

If your partner has cheated on you, think hard about what it means for your relationship and your trust for them. Taking them back or breaking up are both big steps and you will need to know what you have to gain and what you have to lose.

Be aware that the spectre of your partner cheating will haunt your relationship and you will need to be strong to deal with that.