This can happen where a child will only show affection to one parent and does not want to listen to or show affection to the other when they are around. How are your children with you when your wife isn't there. How long have they treated you like this for? What ages are they, if over three it would be worth sitting down with then separately explaining how much you love them and how sad it makes you feel when they are unkind to you. Expressed in a gentle but honest way will help them to understand that it hurts you when they reject you. Equally you should try not to make an issue of it on a regular basis as they may play on it if they see they are getting a reaction whether it be a positive or a negative.
Your wife also needs to encourage then to spend some time with you on a one to one and also as a family and positively reinforce your role within the family. Children are very clever and can play on situations to make them work to there advantage. Its important you take control of the situation without making a big issue of it with them. I hope this helps.
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