Seller financing second property

[Jacob Bogenschuetz]

My realtor and I are exploring seller finance options in our area. My realtor tells me this could impact my current mortgage or that my current lender may not allow it. I've never heard of this issue previously. I'm reaching out to my lender regarding this. 

Can someone comment on this or refer me somewhere with more info on this topic - exploring financing on another property when I hold a mortgage on current property?